chore(release): 4.7.4

Diff: https://github.com/socketio/socket.io/compare/4.7.3...4.7.4

.github/workflows/ci.yml

@@ -36,3 +36,33 @@ jobs:
         run: npm test
         env:
           CI: true
+
+  build-examples:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    strategy:
+      fail-fast: false
+      matrix:
+        example:
+          - custom-parsers
+          - typescript
+          - webpack-build
+          - webpack-build-server
+          - basic-crud-application/angular-client
+          - basic-crud-application/vue-client
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+
+      - name: Use Node.js 20
+        uses: actions/setup-node@v3
+        with:
+          node-version: 20
+
+      - name: Build ${{ matrix.example }}
+        run: |
+          cd examples/${{ matrix.example }}
+          npm install
+          npm run build

CHANGELOG.md

@@ -1,5 +1,10 @@
 # History
 
+## 2024
+
+- [4.7.4](#474-2024-01-12) (Jan 2024)
+- [4.7.3](#473-2024-01-03) (Jan 2024)
+
 ## 2023
 
 - [4.7.2](#472-2023-08-02) (Aug 2023)
@@ -61,6 +66,37 @@
 
 # Release notes
 
+## [4.7.4](https://github.com/socketio/socket.io/compare/4.7.3...4.7.4) (2024-01-12)
+
+
+### Bug Fixes
+
+* **typings:** calling io.emit with no arguments incorrectly errored ([cb6d2e0](https://github.com/socketio/socket.io/commit/cb6d2e02aa7ec03c2de1817d35cffa1128b107ef)), closes [#4914](https://github.com/socketio/socket.io/issues/4914)
+
+
+### Dependencies
+
+- [`engine.io@~6.5.2`](https://github.com/socketio/engine.io/releases/tag/6.5.2) (no change)
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
+
+
+
+## [4.7.3](https://github.com/socketio/socket.io/compare/4.7.2...4.7.3) (2024-01-03)
+
+
+### Bug Fixes
+
+* return the first response when broadcasting to a single socket ([#4878](https://github.com/socketio/socket.io/issues/4878)) ([df8e70f](https://github.com/socketio/socket.io/commit/df8e70f79822e3887b4f21ca718af8a53bbda2c4))
+* **typings:** allow to bind to a non-secure Http2Server ([#4853](https://github.com/socketio/socket.io/issues/4853)) ([8c9ebc3](https://github.com/socketio/socket.io/commit/8c9ebc30e5452ff9381af5d79f547394fa55633c))
+
+
+### Dependencies
+
+- [`engine.io@~6.5.2`](https://github.com/socketio/engine.io/releases/tag/6.5.2) (no change)
+- [`ws@~8.11.0`](https://github.com/websockets/ws/releases/tag/8.11.0) (no change)
+
+
+
 ## [4.7.2](https://github.com/socketio/socket.io/compare/4.7.1...4.7.2) (2023-08-02)
 
 
@@ -855,7 +891,7 @@ new Server(3000, {
 const socket = io("/admin");
 
 // server-side
-io.on("connect", socket => {
+io.on("connection", socket => {
   // not triggered anymore
 })
 
@@ -1006,7 +1042,7 @@ new Server(3000, {
 const socket = io("/admin");
 
 // server-side
-io.on("connect", socket => {
+io.on("connection", socket => {
   // not triggered anymore
 })
 

Readme.md

@@ -22,6 +22,7 @@ Some implementations in other languages are also available:
 - [Python](https://github.com/miguelgrinberg/python-socketio)
 - [.NET](https://github.com/doghappy/socket.io-client-csharp)
 - [Rust](https://github.com/1c3t3a/rust-socketio)
+- [PHP](https://github.com/ElephantIO/elephant.io)
 
 Its main features are:
 

client-dist/socket.io.js

@@ -1,6 +1,6 @@
 /*!
- * Socket.IO v4.7.2
- * (c) 2014-2023 Guillermo Rauch
+ * Socket.IO v4.7.4
+ * (c) 2014-2024 Guillermo Rauch
  * Released under the MIT License.
  */
 (function (global, factory) {

examples/angular-todomvc/server.ts

@@ -15,7 +15,7 @@ interface Todo {
 
 let todos: Array<Todo> = [];
 
-io.on("connect", (socket) => {
+io.on("connection", (socket) => {
     socket.emit("todos", todos);
 
     // note: we could also create a CRUD (create/read/update/delete) service for the todo list

examples/basic-crud-application/angular-client/.browserslistrc

@@ -1,17 +0,0 @@
-# This file is used by the build system to adjust CSS and JS output to support the specified browsers below.
-# For additional information regarding the format and rule options, please see:
-# https://github.com/browserslist/browserslist#queries
-
-# For the full list of supported browsers by the Angular framework, please see:
-# https://angular.io/guide/browser-support
-
-# You can see what browsers were selected by your queries by running:
-#   npx browserslist
-
-last 1 Chrome version
-last 1 Firefox version
-last 2 Edge major versions
-last 2 Safari major versions
-last 2 iOS major versions
-Firefox ESR
-not IE 11 # Angular supports IE 11 only as an opt-in. To opt-in, remove the 'not' prefix on this line.

examples/basic-crud-application/angular-client/.gitignore

@@ -1,21 +1,18 @@
 # See http://help.github.com/ignore-files/ for more about ignoring files.
 
-# compiled output
+# Compiled output
 /dist
 /tmp
 /out-tsc
-# Only exists if Bazel was run
 /bazel-out
 
-# dependencies
+# Node
 /node_modules
-
-# profiling files
-chrome-profiler-events*.json
-speed-measure-plugin*.json
+npm-debug.log
+yarn-error.log
 
 # IDEs and editors
-/.idea
+.idea/
 .project
 .classpath
 .c9/
@@ -23,7 +20,7 @@ speed-measure-plugin*.json
 .settings/
 *.sublime-workspace
 
-# IDE - VSCode
+# Visual Studio Code
 .vscode/*
 !.vscode/settings.json
 !.vscode/tasks.json
@@ -31,16 +28,15 @@ speed-measure-plugin*.json
 !.vscode/extensions.json
 .history/*
 
-# misc
-/.sass-cache
+# Miscellaneous
+/.angular/cache
+.sass-cache/
 /connect.lock
 /coverage
 /libpeerconnection.log
-npm-debug.log
-yarn-error.log
 testem.log
 /typings
 
-# System Files
+# System files
 .DS_Store
 Thumbs.db

examples/basic-crud-application/angular-client/README.md

@@ -1,14 +1,10 @@
-# Angular TodoMVC + Socket.IO
+# AngularClient
 
-This project was generated with [Angular CLI](https://github.com/angular/angular-cli) version 11.0.4.
-
-Inspired from the [TodoMVC](http://todomvc.com/) [angular example](https://github.com/tastejs/todomvc/tree/master/examples/angular2).
-
-![demo](assets/demo.gif)
+This project was generated with [Angular CLI](https://github.com/angular/angular-cli) version 17.0.2.
 
 ## Development server
 
-Run `ng serve` for a dev server. Navigate to `http://localhost:4200/`. The app will automatically reload if you change any of the source files.
+Run `ng serve` for a dev server. Navigate to `http://localhost:4200/`. The application will automatically reload if you change any of the source files.
 
 ## Code scaffolding
 
@@ -16,7 +12,7 @@ Run `ng generate component component-name` to generate a new component. You can
 
 ## Build
 
-Run `ng build` to build the project. The build artifacts will be stored in the `dist/` directory. Use the `--prod` flag for a production build.
+Run `ng build` to build the project. The build artifacts will be stored in the `dist/` directory.
 
 ## Running unit tests
 
@@ -24,7 +20,7 @@ Run `ng test` to execute the unit tests via [Karma](https://karma-runner.github.
 
 ## Running end-to-end tests
 
-Run `ng e2e` to execute the end-to-end tests via [Protractor](http://www.protractortest.org/).
+Run `ng e2e` to execute the end-to-end tests via a platform of your choice. To use this command, you need to first add a package that implements end-to-end testing capabilities.
 
 ## Further help
 

examples/basic-crud-application/angular-client/angular.json

@@ -3,26 +3,23 @@
   "version": 1,
   "newProjectRoot": "projects",
   "projects": {
-    "angular-todomvc": {
+    "angular-client": {
       "projectType": "application",
-      "schematics": {
-        "@schematics/angular:application": {
-          "strict": true
-        }
-      },
+      "schematics": {},
       "root": "",
       "sourceRoot": "src",
       "prefix": "app",
       "architect": {
         "build": {
-          "builder": "@angular-devkit/build-angular:browser",
+          "builder": "@angular-devkit/build-angular:application",
           "options": {
-            "outputPath": "dist/angular-todomvc",
+            "outputPath": "dist/angular-client",
             "index": "src/index.html",
-            "main": "src/main.ts",
-            "polyfills": "src/polyfills.ts",
+            "browser": "src/main.ts",
+            "polyfills": [
+              "zone.js"
+            ],
             "tsConfig": "tsconfig.app.json",
-            "aot": true,
             "assets": [
               "src/favicon.ico",
               "src/assets"
@@ -34,19 +31,6 @@
           },
           "configurations": {
             "production": {
-              "fileReplacements": [
-                {
-                  "replace": "src/environments/environment.ts",
-                  "with": "src/environments/environment.prod.ts"
-                }
-              ],
-              "optimization": true,
-              "outputHashing": "all",
-              "sourceMap": false,
-              "namedChunks": false,
-              "extractLicenses": true,
-              "vendorChunk": false,
-              "buildOptimizer": true,
               "budgets": [
                 {
                   "type": "initial",
@@ -58,34 +42,49 @@
                   "maximumWarning": "2kb",
                   "maximumError": "4kb"
                 }
+              ],
+              "outputHashing": "all"
+            },
+            "development": {
+              "optimization": false,
+              "extractLicenses": false,
+              "sourceMap": true,
+              "fileReplacements": [
+                {
+                  "replace": "src/environments/environment.ts",
+                  "with": "src/environments/environment.development.ts"
+                }
               ]
             }
-          }
+          },
+          "defaultConfiguration": "production"
         },
         "serve": {
           "builder": "@angular-devkit/build-angular:dev-server",
-          "options": {
-            "browserTarget": "angular-todomvc:build"
-          },
           "configurations": {
             "production": {
-              "browserTarget": "angular-todomvc:build:production"
+              "buildTarget": "angular-client:build:production"
+            },
+            "development": {
+              "buildTarget": "angular-client:build:development"
             }
-          }
+          },
+          "defaultConfiguration": "development"
         },
         "extract-i18n": {
           "builder": "@angular-devkit/build-angular:extract-i18n",
           "options": {
-            "browserTarget": "angular-todomvc:build"
+            "buildTarget": "angular-client:build"
           }
         },
         "test": {
           "builder": "@angular-devkit/build-angular:karma",
           "options": {
-            "main": "src/test.ts",
-            "polyfills": "src/polyfills.ts",
+            "polyfills": [
+              "zone.js",
+              "zone.js/testing"
+            ],
             "tsConfig": "tsconfig.spec.json",
-            "karmaConfig": "karma.conf.js",
             "assets": [
               "src/favicon.ico",
               "src/assets"
@@ -95,34 +94,8 @@
             ],
             "scripts": []
           }
-        },
-        "lint": {
-          "builder": "@angular-devkit/build-angular:tslint",
-          "options": {
-            "tsConfig": [
-              "tsconfig.app.json",
-              "tsconfig.spec.json",
-              "e2e/tsconfig.json"
-            ],
-            "exclude": [
-              "**/node_modules/**"
-            ]
-          }
-        },
-        "e2e": {
-          "builder": "@angular-devkit/build-angular:protractor",
-          "options": {
-            "protractorConfig": "e2e/protractor.conf.js",
-            "devServerTarget": "angular-todomvc:serve"
-          },
-          "configurations": {
-            "production": {
-              "devServerTarget": "angular-todomvc:serve:production"
-            }
-          }
         }
       }
     }
-  },
-  "defaultProject": "angular-todomvc"
+  }
 }

examples/basic-crud-application/angular-client/e2e/protractor.conf.js

@@ -1,37 +0,0 @@
-// @ts-check
-// Protractor configuration file, see link for more information
-// https://github.com/angular/protractor/blob/master/lib/config.ts
-
-const { SpecReporter, StacktraceOption } = require('jasmine-spec-reporter');
-
-/**
- * @type { import("protractor").Config }
- */
-exports.config = {
-  allScriptsTimeout: 11000,
-  specs: [
-    './src/**/*.e2e-spec.ts'
-  ],
-  capabilities: {
-    browserName: 'chrome'
-  },
-  directConnect: true,
-  SELENIUM_PROMISE_MANAGER: false,
-  baseUrl: 'http://localhost:4200/',
-  framework: 'jasmine',
-  jasmineNodeOpts: {
-    showColors: true,
-    defaultTimeoutInterval: 30000,
-    print: function() {}
-  },
-  onPrepare() {
-    require('ts-node').register({
-      project: require('path').join(__dirname, './tsconfig.json')
-    });
-    jasmine.getEnv().addReporter(new SpecReporter({
-      spec: {
-        displayStacktrace: StacktraceOption.PRETTY
-      }
-    }));
-  }
-};

examples/basic-crud-application/angular-client/e2e/src/app.e2e-spec.ts

@@ -1,23 +0,0 @@
-import { AppPage } from './app.po';
-import { browser, logging } from 'protractor';
-
-describe('workspace-project App', () => {
-  let page: AppPage;
-
-  beforeEach(() => {
-    page = new AppPage();
-  });
-
-  it('should display welcome message', async () => {
-    await page.navigateTo();
-    expect(await page.getTitleText()).toEqual('angular-todomvc app is running!');
-  });
-
-  afterEach(async () => {
-    // Assert that there are no errors emitted from the browser
-    const logs = await browser.manage().logs().get(logging.Type.BROWSER);
-    expect(logs).not.toContain(jasmine.objectContaining({
-      level: logging.Level.SEVERE,
-    } as logging.Entry));
-  });
-});

examples/basic-crud-application/angular-client/e2e/src/app.po.ts

@@ -1,11 +0,0 @@
-import { browser, by, element } from 'protractor';
-
-export class AppPage {
-  async navigateTo(): Promise<unknown> {
-    return browser.get(browser.baseUrl);
-  }
-
-  async getTitleText(): Promise<string> {
-    return element(by.css('app-root .content span')).getText();
-  }
-}

examples/basic-crud-application/angular-client/e2e/tsconfig.json

@@ -1,13 +0,0 @@
-/* To learn more about this file see: https://angular.io/config/tsconfig. */
-{
-  "extends": "../tsconfig.json",
-  "compilerOptions": {
-    "outDir": "../out-tsc/e2e",
-    "module": "commonjs",
-    "target": "es2018",
-    "types": [
-      "jasmine",
-      "node"
-    ]
-  }
-}

examples/basic-crud-application/angular-client/karma.conf.js

@@ -1,44 +0,0 @@
-// Karma configuration file, see link for more information
-// https://karma-runner.github.io/1.0/config/configuration-file.html
-
-module.exports = function (config) {
-  config.set({
-    basePath: '',
-    frameworks: ['jasmine', '@angular-devkit/build-angular'],
-    plugins: [
-      require('karma-jasmine'),
-      require('karma-chrome-launcher'),
-      require('karma-jasmine-html-reporter'),
-      require('karma-coverage'),
-      require('@angular-devkit/build-angular/plugins/karma')
-    ],
-    client: {
-      jasmine: {
-        // you can add configuration options for Jasmine here
-        // the possible options are listed at https://jasmine.github.io/api/edge/Configuration.html
-        // for example, you can disable the random execution with `random: false`
-        // or set a specific seed with `seed: 4321`
-      },
-      clearContext: false // leave Jasmine Spec Runner output visible in browser
-    },
-    jasmineHtmlReporter: {
-      suppressAll: true // removes the duplicated traces
-    },
-    coverageReporter: {
-      dir: require('path').join(__dirname, './coverage/angular-todomvc'),
-      subdir: '.',
-      reporters: [
-        { type: 'html' },
-        { type: 'text-summary' }
-      ]
-    },
-    reporters: ['progress', 'kjhtml'],
-    port: 9876,
-    colors: true,
-    logLevel: config.LOG_INFO,
-    autoWatch: true,
-    browsers: ['Chrome'],
-    singleRun: false,
-    restartOnFileChange: true
-  });
-};

examples/basic-crud-application/angular-client/package.json

@@ -1,46 +1,40 @@
 {
-  "name": "angular-todomvc",
+  "name": "angular-client",
   "version": "0.0.0",
   "scripts": {
     "ng": "ng",
     "start": "ng serve",
     "build": "ng build",
-    "test": "ng test",
-    "lint": "ng lint",
-    "e2e": "ng e2e"
+    "watch": "ng build --watch --configuration development",
+    "test": "ng test"
   },
   "private": true,
   "dependencies": {
-    "@angular/animations": "~11.0.4",
-    "@angular/common": "~11.0.4",
-    "@angular/compiler": "~11.0.4",
-    "@angular/core": "~11.0.4",
-    "@angular/forms": "~11.0.4",
-    "@angular/platform-browser": "~11.0.4",
-    "@angular/platform-browser-dynamic": "~11.0.4",
-    "@angular/router": "~11.0.4",
-    "rxjs": "~6.6.0",
-    "socket.io-client": "^4.0.0",
-    "tslib": "^2.0.0",
-    "zone.js": "~0.10.2"
+    "@angular/animations": "^17.0.0",
+    "@angular/common": "^17.0.0",
+    "@angular/compiler": "^17.0.0",
+    "@angular/core": "^17.0.0",
+    "@angular/forms": "^17.0.0",
+    "@angular/platform-browser": "^17.0.0",
+    "@angular/platform-browser-dynamic": "^17.0.0",
+    "@angular/router": "^17.0.0",
+    "rxjs": "~7.8.0",
+    "socket.io-client": "^4.7.2",
+    "tslib": "^2.3.0",
+    "zone.js": "~0.14.2"
   },
   "devDependencies": {
-    "@angular-devkit/build-angular": "~0.1100.4",
-    "@angular/cli": "~11.0.4",
-    "@angular/compiler-cli": "~11.0.4",
-    "@types/jasmine": "~3.6.0",
-    "@types/node": "^12.11.1",
-    "codelyzer": "^6.0.0",
-    "jasmine-core": "~3.6.0",
-    "jasmine-spec-reporter": "~5.0.0",
-    "karma": "~5.1.0",
-    "karma-chrome-launcher": "~3.1.0",
-    "karma-coverage": "~2.0.3",
-    "karma-jasmine": "~4.0.0",
-    "karma-jasmine-html-reporter": "~1.5.0",
-    "protractor": "~7.0.0",
-    "ts-node": "~8.3.0",
-    "tslint": "~6.1.0",
-    "typescript": "~4.0.2"
+    "@angular-devkit/build-angular": "^17.0.2",
+    "@angular/cli": "^17.0.2",
+    "@angular/compiler-cli": "^17.0.0",
+    "@types/jasmine": "~5.1.0",
+    "@types/node": "^20.9.2",
+    "jasmine-core": "~5.1.0",
+    "karma": "~6.4.0",
+    "karma-chrome-launcher": "~3.2.0",
+    "karma-coverage": "~2.2.0",
+    "karma-jasmine": "~5.1.0",
+    "karma-jasmine-html-reporter": "~2.1.0",
+    "typescript": "~5.2.2"
   }
 }

examples/basic-crud-application/angular-client/src/app/app.component.html

@@ -1,7 +1,8 @@
 <section class="todoapp">
   <header class="header">
     <h1>todos</h1>
-    <input class="new-todo" placeholder="What needs to be done?" autofocus="" [(ngModel)]="newTodoText" (keyup.enter)="addTodo()">
+<!--    <input class="new-todo" placeholder="What needs to be done?" autofocus="" [(ngModel)]="newTodoText" (keyup.enter)="addTodo()">-->
+    <input class="new-todo" placeholder="What needs to be done?" autofocus="" [formControl]="newTodoText" (keyup.enter)="addTodo()">
   </header>
   <section class="main" *ngIf="todoStore.todos.length > 0">
     <input id="toggle-all" class="toggle-all" type="checkbox" *ngIf="todoStore.todos.length" #toggleall [checked]="todoStore.allCompleted()" (click)="todoStore.setAllTo(toggleall.checked)">

examples/basic-crud-application/angular-client/src/app/app.component.spec.ts

@@ -4,9 +4,7 @@ import { AppComponent } from './app.component';
 describe('AppComponent', () => {
   beforeEach(async () => {
     await TestBed.configureTestingModule({
-      declarations: [
-        AppComponent
-      ],
+      imports: [AppComponent],
     }).compileComponents();
   });
 
@@ -16,16 +14,16 @@ describe('AppComponent', () => {
     expect(app).toBeTruthy();
   });
 
-  it(`should have as title 'angular-todomvc'`, () => {
+  it(`should have the 'angular-client' title`, () => {
     const fixture = TestBed.createComponent(AppComponent);
     const app = fixture.componentInstance;
-    expect(app.title).toEqual('angular-todomvc');
+    expect(app.title).toEqual('angular-client');
   });
 
   it('should render title', () => {
     const fixture = TestBed.createComponent(AppComponent);
     fixture.detectChanges();
-    const compiled = fixture.nativeElement;
-    expect(compiled.querySelector('.content span').textContent).toContain('angular-todomvc app is running!');
+    const compiled = fixture.nativeElement as HTMLElement;
+    expect(compiled.querySelector('h1')?.textContent).toContain('Hello, angular-client');
   });
 });

examples/basic-crud-application/angular-client/src/app/app.component.ts

@@ -1,17 +1,21 @@
 import { Component } from '@angular/core';
-import { TodoStore, Todo } from './store';
+import { CommonModule } from '@angular/common';
+import { RouterOutlet } from '@angular/router';
+import {type Todo, TodoStore} from "./store";
+import { FormControl, ReactiveFormsModule } from '@angular/forms';
 
 @Component({
   selector: 'app-root',
+  standalone: true,
+  imports: [CommonModule, RouterOutlet, ReactiveFormsModule],
   templateUrl: './app.component.html',
-  styleUrls: ['./app.component.css']
+  styleUrl: './app.component.css',
+  providers: [TodoStore]
 })
 export class AppComponent {
-  todoStore: TodoStore;
-  newTodoText = '';
+  newTodoText = new FormControl('');
 
-  constructor(todoStore: TodoStore) {
-    this.todoStore = todoStore;
+  constructor(readonly todoStore: TodoStore) {
   }
 
   stopEditing(todo: Todo, editedTitle: string) {
@@ -51,9 +55,9 @@ export class AppComponent {
   }
 
   addTodo() {
-    if (this.newTodoText.trim().length) {
-      this.todoStore.add(this.newTodoText);
-      this.newTodoText = '';
+    if (this.newTodoText.value?.trim().length) {
+      this.todoStore.add(this.newTodoText.value!);
+      this.newTodoText.setValue('');
     }
   }
 }

examples/basic-crud-application/angular-client/src/app/app.config.ts

@@ -0,0 +1,8 @@
+import { ApplicationConfig } from '@angular/core';
+import { provideRouter } from '@angular/router';
+
+import { routes } from './app.routes';
+
+export const appConfig: ApplicationConfig = {
+  providers: [provideRouter(routes)]
+};

examples/basic-crud-application/angular-client/src/app/app.module.ts

@@ -1,19 +0,0 @@
-import { BrowserModule } from '@angular/platform-browser';
-import { NgModule } from '@angular/core';
-
-import { AppComponent } from './app.component';
-import { TodoStore } from './store';
-import { FormsModule } from "@angular/forms";
-
-@NgModule({
-  declarations: [
-    AppComponent
-  ],
-  imports: [
-    BrowserModule,
-    FormsModule
-  ],
-  providers: [TodoStore],
-  bootstrap: [AppComponent]
-})
-export class AppModule { }

examples/basic-crud-application/angular-client/src/app/app.routes.ts

@@ -0,0 +1,3 @@
+import { Routes } from '@angular/router';
+
+export const routes: Routes = [];

examples/basic-crud-application/angular-client/src/app/store.ts

@@ -1,6 +1,7 @@
 import { io, Socket } from "socket.io-client";
-import { ClientEvents, ServerEvents } from "../../../server/lib/events";
+import { ClientEvents, ServerEvents } from "../../../common/events";
 import { environment } from '../environments/environment';
+import {Injectable} from "@angular/core";
 
 export interface Todo {
   id: string,
@@ -18,6 +19,7 @@ const mapTodo = (todo: any) => {
   }
 }
 
+@Injectable()
 export class TodoStore {
   public todos: Array<Todo> = [];
   private socket: Socket<ServerEvents, ClientEvents>;

examples/basic-crud-application/angular-client/src/environments/environment.development.ts

@@ -0,0 +1,3 @@
+export const environment = {
+  serverUrl: "http://localhost:3000"
+};

examples/basic-crud-application/angular-client/src/environments/environment.prod.ts

@@ -1,4 +0,0 @@
-export const environment = {
-  production: true,
-  serverUrl: "https://my-custom-domain.com"
-};

examples/basic-crud-application/angular-client/src/environments/environment.ts

@@ -1,17 +1,3 @@
-// This file can be replaced during build by using the `fileReplacements` array.
-// `ng build --prod` replaces `environment.ts` with `environment.prod.ts`.
-// The list of file replacements can be found in `angular.json`.
-
 export const environment = {
-  production: false,
-  serverUrl: "http://localhost:3000"
+  serverUrl: "https://my-custom-domain.com"
 };
-
-/*
- * For easier debugging in development mode, you can import the following file
- * to ignore zone related error stack frames such as `zone.run`, `zoneDelegate.invokeTask`.
- *
- * This import should be commented out in production mode because it will have a negative impact
- * on performance if an error is thrown.
- */
-// import 'zone.js/dist/zone-error';  // Included with Angular CLI.

examples/basic-crud-application/angular-client/src/index.html

@@ -2,7 +2,7 @@
 <html lang="en">
 <head>
   <meta charset="utf-8">
-  <title>Angular Todo MVC</title>
+  <title>AngularClient</title>
   <base href="/">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <link rel="icon" type="image/x-icon" href="favicon.ico">

examples/basic-crud-application/angular-client/src/main.ts

@@ -1,12 +1,6 @@
-import { enableProdMode } from '@angular/core';
-import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
+import { bootstrapApplication } from '@angular/platform-browser';
+import { appConfig } from './app/app.config';
+import { AppComponent } from './app/app.component';
 
-import { AppModule } from './app/app.module';
-import { environment } from './environments/environment';
-
-if (environment.production) {
-  enableProdMode();
-}
-
-platformBrowserDynamic().bootstrapModule(AppModule)
-  .catch(err => console.error(err));
+bootstrapApplication(AppComponent, appConfig)
+  .catch((err) => console.error(err));

examples/basic-crud-application/angular-client/src/polyfills.ts

@@ -1,63 +0,0 @@
-/**
- * This file includes polyfills needed by Angular and is loaded before the app.
- * You can add your own extra polyfills to this file.
- *
- * This file is divided into 2 sections:
- *   1. Browser polyfills. These are applied before loading ZoneJS and are sorted by browsers.
- *   2. Application imports. Files imported after ZoneJS that should be loaded before your main
- *      file.
- *
- * The current setup is for so-called "evergreen" browsers; the last versions of browsers that
- * automatically update themselves. This includes Safari >= 10, Chrome >= 55 (including Opera),
- * Edge >= 13 on the desktop, and iOS 10 and Chrome on mobile.
- *
- * Learn more in https://angular.io/guide/browser-support
- */
-
-/***************************************************************************************************
- * BROWSER POLYFILLS
- */
-
-/** IE11 requires the following for NgClass support on SVG elements */
-// import 'classlist.js';  // Run `npm install --save classlist.js`.
-
-/**
- * Web Animations `@angular/platform-browser/animations`
- * Only required if AnimationBuilder is used within the application and using IE/Edge or Safari.
- * Standard animation support in Angular DOES NOT require any polyfills (as of Angular 6.0).
- */
-// import 'web-animations-js';  // Run `npm install --save web-animations-js`.
-
-/**
- * By default, zone.js will patch all possible macroTask and DomEvents
- * user can disable parts of macroTask/DomEvents patch by setting following flags
- * because those flags need to be set before `zone.js` being loaded, and webpack
- * will put import in the top of bundle, so user need to create a separate file
- * in this directory (for example: zone-flags.ts), and put the following flags
- * into that file, and then add the following code before importing zone.js.
- * import './zone-flags';
- *
- * The flags allowed in zone-flags.ts are listed here.
- *
- * The following flags will work for all browsers.
- *
- * (window as any).__Zone_disable_requestAnimationFrame = true; // disable patch requestAnimationFrame
- * (window as any).__Zone_disable_on_property = true; // disable patch onProperty such as onclick
- * (window as any).__zone_symbol__UNPATCHED_EVENTS = ['scroll', 'mousemove']; // disable patch specified eventNames
- *
- *  in IE/Edge developer tools, the addEventListener will also be wrapped by zone.js
- *  with the following flag, it will bypass `zone.js` patch for IE/Edge
- *
- *  (window as any).__Zone_enable_cross_context_check = true;
- *
- */
-
-/***************************************************************************************************
- * Zone JS is required by default for Angular itself.
- */
-import 'zone.js/dist/zone';  // Included with Angular CLI.
-
-
-/***************************************************************************************************
- * APPLICATION IMPORTS
- */

examples/basic-crud-application/angular-client/src/test.ts

@@ -1,25 +0,0 @@
-// This file is required by karma.conf.js and loads recursively all the .spec and framework files
-
-import 'zone.js/dist/zone-testing';
-import { getTestBed } from '@angular/core/testing';
-import {
-  BrowserDynamicTestingModule,
-  platformBrowserDynamicTesting
-} from '@angular/platform-browser-dynamic/testing';
-
-declare const require: {
-  context(path: string, deep?: boolean, filter?: RegExp): {
-    keys(): string[];
-    <T>(id: string): T;
-  };
-};
-
-// First, initialize the Angular testing environment.
-getTestBed().initTestEnvironment(
-  BrowserDynamicTestingModule,
-  platformBrowserDynamicTesting()
-);
-// Then we find all the tests.
-const context = require.context('./', true, /\.spec\.ts$/);
-// And load the modules.
-context.keys().map(context);

examples/basic-crud-application/angular-client/tsconfig.app.json

@@ -6,8 +6,7 @@
     "types": []
   },
   "files": [
-    "src/main.ts",
-    "src/polyfills.ts"
+    "src/main.ts"
   ],
   "include": [
     "src/**/*.d.ts"

examples/basic-crud-application/angular-client/tsconfig.json

@@ -2,26 +2,29 @@
 {
   "compileOnSave": false,
   "compilerOptions": {
-    "baseUrl": "./",
     "outDir": "./dist/out-tsc",
     "forceConsistentCasingInFileNames": true,
     "strict": true,
+    "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
+    "esModuleInterop": true,
     "sourceMap": true,
     "declaration": false,
-    "downlevelIteration": true,
     "experimentalDecorators": true,
     "moduleResolution": "node",
     "importHelpers": true,
-    "target": "es2015",
-    "module": "es2020",
+    "target": "ES2022",
+    "module": "ES2022",
+    "useDefineForClassFields": false,
     "lib": [
-      "es2018",
+      "ES2022",
       "dom"
     ]
   },
   "angularCompilerOptions": {
+    "enableI18nLegacyMessageIdFormat": false,
     "strictInjectionParameters": true,
     "strictInputAccessModifiers": true,
     "strictTemplates": true

examples/basic-crud-application/angular-client/tsconfig.spec.json

@@ -7,10 +7,6 @@
       "jasmine"
     ]
   },
-  "files": [
-    "src/test.ts",
-    "src/polyfills.ts"
-  ],
   "include": [
     "src/**/*.spec.ts",
     "src/**/*.d.ts"

examples/basic-crud-application/angular-client/tslint.json

@@ -1,152 +0,0 @@
-{
-  "extends": "tslint:recommended",
-  "rulesDirectory": [
-    "codelyzer"
-  ],
-  "rules": {
-    "align": {
-      "options": [
-        "parameters",
-        "statements"
-      ]
-    },
-    "array-type": false,
-    "arrow-return-shorthand": true,
-    "curly": true,
-    "deprecation": {
-      "severity": "warning"
-    },
-    "eofline": true,
-    "import-blacklist": [
-      true,
-      "rxjs/Rx"
-    ],
-    "import-spacing": true,
-    "indent": {
-      "options": [
-        "spaces"
-      ]
-    },
-    "max-classes-per-file": false,
-    "max-line-length": [
-      true,
-      140
-    ],
-    "member-ordering": [
-      true,
-      {
-        "order": [
-          "static-field",
-          "instance-field",
-          "static-method",
-          "instance-method"
-        ]
-      }
-    ],
-    "no-console": [
-      true,
-      "debug",
-      "info",
-      "time",
-      "timeEnd",
-      "trace"
-    ],
-    "no-empty": false,
-    "no-inferrable-types": [
-      true,
-      "ignore-params"
-    ],
-    "no-non-null-assertion": true,
-    "no-redundant-jsdoc": true,
-    "no-switch-case-fall-through": true,
-    "no-var-requires": false,
-    "object-literal-key-quotes": [
-      true,
-      "as-needed"
-    ],
-    "quotemark": [
-      true,
-      "single"
-    ],
-    "semicolon": {
-      "options": [
-        "always"
-      ]
-    },
-    "space-before-function-paren": {
-      "options": {
-        "anonymous": "never",
-        "asyncArrow": "always",
-        "constructor": "never",
-        "method": "never",
-        "named": "never"
-      }
-    },
-    "typedef": [
-      true,
-      "call-signature"
-    ],
-    "typedef-whitespace": {
-      "options": [
-        {
-          "call-signature": "nospace",
-          "index-signature": "nospace",
-          "parameter": "nospace",
-          "property-declaration": "nospace",
-          "variable-declaration": "nospace"
-        },
-        {
-          "call-signature": "onespace",
-          "index-signature": "onespace",
-          "parameter": "onespace",
-          "property-declaration": "onespace",
-          "variable-declaration": "onespace"
-        }
-      ]
-    },
-    "variable-name": {
-      "options": [
-        "ban-keywords",
-        "check-format",
-        "allow-pascal-case"
-      ]
-    },
-    "whitespace": {
-      "options": [
-        "check-branch",
-        "check-decl",
-        "check-operator",
-        "check-separator",
-        "check-type",
-        "check-typecast"
-      ]
-    },
-    "component-class-suffix": true,
-    "contextual-lifecycle": true,
-    "directive-class-suffix": true,
-    "no-conflicting-lifecycle": true,
-    "no-host-metadata-property": true,
-    "no-input-rename": true,
-    "no-inputs-metadata-property": true,
-    "no-output-native": true,
-    "no-output-on-prefix": true,
-    "no-output-rename": true,
-    "no-outputs-metadata-property": true,
-    "template-banana-in-box": true,
-    "template-no-negated-async": true,
-    "use-lifecycle-interface": true,
-    "use-pipe-transform-interface": true,
-    "directive-selector": [
-      true,
-      "attribute",
-      "app",
-      "camelCase"
-    ],
-    "component-selector": [
-      true,
-      "element",
-      "app",
-      "kebab-case"
-    ]
-  }
-}

examples/basic-crud-application/common/events.ts

@@ -1,9 +1,18 @@
-import { Todo, TodoID } from "./todo-management/todo.repository";
-import { ValidationErrorItem } from "joi";
+export type TodoID = string;
+
+export interface Todo {
+  id: TodoID;
+  completed: boolean;
+  title: string;
+}
 
 interface Error {
   error: string;
-  errorDetails?: ValidationErrorItem[];
+  errorDetails?: {
+    message: string;
+    path: Array<string | number>;
+    type: string;
+  }[];
 }
 
 interface Success<T> {

examples/basic-crud-application/server/lib/app.ts

@@ -1,6 +1,6 @@
 import { Server as HttpServer } from "http";
 import { Server, ServerOptions } from "socket.io";
-import { ClientEvents, ServerEvents } from "./events";
+import { ClientEvents, ServerEvents } from "../../common/events";
 import { TodoRepository } from "./todo-management/todo.repository";
 import createTodoHandlers from "./todo-management/todo.handlers";
 

examples/basic-crud-application/server/lib/todo-management/todo.handlers.ts

@@ -2,8 +2,13 @@ import { Errors, mapErrorDetails, sanitizeErrorMessage } from "../util";
 import { v4 as uuid } from "uuid";
 import { Components } from "../app";
 import Joi = require("joi");
-import { Todo, TodoID } from "./todo.repository";
-import { ClientEvents, Response, ServerEvents } from "../events";
+import {
+  Todo,
+  TodoID,
+  ClientEvents,
+  Response,
+  ServerEvents,
+} from "../../../common/events";
 import { Socket } from "socket.io";
 
 const idSchema = Joi.string().guid({
@@ -19,8 +24,7 @@ const todoSchema = Joi.object({
   completed: Joi.boolean().required(),
 });
 
-export default function (components: Components) {
-  const { todoRepository } = components;
+export default function ({ todoRepository }: Components) {
   return {
     createTodo: async function (
       payload: Omit<Todo, "id">,

examples/basic-crud-application/server/lib/todo-management/todo.repository.ts

@@ -1,4 +1,5 @@
 import { Errors } from "../util";
+import { Todo, TodoID } from "../../../common/events";
 
 abstract class CrudRepository<T, ID> {
   abstract findAll(): Promise<T[]>;
@@ -7,14 +8,6 @@ abstract class CrudRepository<T, ID> {
   abstract deleteById(id: ID): Promise<void>;
 }
 
-export type TodoID = string;
-
-export interface Todo {
-  id: TodoID;
-  completed: boolean;
-  title: string;
-}
-
 export abstract class TodoRepository extends CrudRepository<Todo, TodoID> {}
 
 export class InMemoryTodoRepository extends TodoRepository {

examples/basic-crud-application/vue-client/.gitignore

@@ -0,0 +1,23 @@
+.DS_Store
+node_modules
+/dist
+
+
+# local env files
+.env.local
+.env.*.local
+
+# Log files
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+
+# Editor directories and files
+.idea
+.vscode
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?

examples/basic-crud-application/vue-client/README.md

@@ -0,0 +1,24 @@
+# vue-client
+
+## Project setup
+```
+yarn install
+```
+
+### Compiles and hot-reloads for development
+```
+yarn serve
+```
+
+### Compiles and minifies for production
+```
+yarn build
+```
+
+### Lints and fixes files
+```
+yarn lint
+```
+
+### Customize configuration
+See [Configuration Reference](https://cli.vuejs.org/config/).

examples/basic-crud-application/vue-client/babel.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+  presets: [
+    '@vue/cli-plugin-babel/preset'
+  ]
+}

examples/basic-crud-application/vue-client/jsconfig.json

@@ -0,0 +1,19 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "module": "esnext",
+    "baseUrl": "./",
+    "moduleResolution": "node",
+    "paths": {
+      "@/*": [
+        "src/*"
+      ]
+    },
+    "lib": [
+      "esnext",
+      "dom",
+      "dom.iterable",
+      "scripthost"
+    ]
+  }
+}

examples/basic-crud-application/vue-client/package.json

@@ -0,0 +1,45 @@
+{
+  "name": "vue-client",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "serve": "vue-cli-service serve --port 4200",
+    "build": "vue-cli-service build",
+    "lint": "vue-cli-service lint"
+  },
+  "dependencies": {
+    "core-js": "^3.8.3",
+    "pinia": "^2.1.7",
+    "socket.io-client": "^4.7.2",
+    "vue": "^3.2.13"
+  },
+  "devDependencies": {
+    "@babel/core": "^7.12.16",
+    "@babel/eslint-parser": "^7.12.16",
+    "@vue/cli-plugin-babel": "~5.0.0",
+    "@vue/cli-plugin-eslint": "~5.0.0",
+    "@vue/cli-service": "~5.0.0",
+    "eslint": "^7.32.0",
+    "eslint-plugin-vue": "^8.0.3"
+  },
+  "eslintConfig": {
+    "root": true,
+    "env": {
+      "node": true
+    },
+    "extends": [
+      "plugin:vue/vue3-essential",
+      "eslint:recommended"
+    ],
+    "parserOptions": {
+      "parser": "@babel/eslint-parser"
+    },
+    "rules": {}
+  },
+  "browserslist": [
+    "> 1%",
+    "last 2 versions",
+    "not dead",
+    "not ie 11"
+  ]
+}

examples/basic-crud-application/vue-client/public/index.html

@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html lang="">
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="X-UA-Compatible" content="IE=edge">
+    <meta name="viewport" content="width=device-width,initial-scale=1.0">
+    <link rel="icon" href="<%= BASE_URL %>favicon.ico">
+    <link href="styles.css" rel="stylesheet" type="text/css" />
+    <title><%= htmlWebpackPlugin.options.title %></title>
+  </head>
+  <body>
+    <noscript>
+      <strong>We're sorry but <%= htmlWebpackPlugin.options.title %> doesn't work properly without JavaScript enabled. Please enable it to continue.</strong>
+    </noscript>
+    <div id="app"></div>
+    <!-- built files will be auto injected -->
+  </body>
+</html>

examples/basic-crud-application/vue-client/public/styles.css

@@ -0,0 +1,381 @@
+/* imported from node_modules/todomvc-app-css/index.css */
+html,
+body {
+  margin: 0;
+  padding: 0;
+}
+
+button {
+  margin: 0;
+  padding: 0;
+  border: 0;
+  background: none;
+  font-size: 100%;
+  vertical-align: baseline;
+  font-family: inherit;
+  font-weight: inherit;
+  color: inherit;
+  -webkit-appearance: none;
+  appearance: none;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+body {
+  font: 14px 'Helvetica Neue', Helvetica, Arial, sans-serif;
+  line-height: 1.4em;
+  background: #f5f5f5;
+  color: #111111;
+  min-width: 230px;
+  max-width: 550px;
+  margin: 0 auto;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  font-weight: 300;
+}
+
+:focus {
+  outline: 0;
+}
+
+.hidden {
+  display: none;
+}
+
+.todoapp {
+  background: #fff;
+  margin: 130px 0 40px 0;
+  position: relative;
+  box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.2),
+  0 25px 50px 0 rgba(0, 0, 0, 0.1);
+}
+
+.todoapp input::-webkit-input-placeholder {
+  font-style: italic;
+  font-weight: 300;
+  color: rgba(0, 0, 0, 0.4);
+}
+
+.todoapp input::-moz-placeholder {
+  font-style: italic;
+  font-weight: 300;
+  color: rgba(0, 0, 0, 0.4);
+}
+
+.todoapp input::input-placeholder {
+  font-style: italic;
+  font-weight: 300;
+  color: rgba(0, 0, 0, 0.4);
+}
+
+.todoapp h1 {
+  position: absolute;
+  top: -140px;
+  width: 100%;
+  font-size: 80px;
+  font-weight: 200;
+  text-align: center;
+  color: #b83f45;
+  -webkit-text-rendering: optimizeLegibility;
+  -moz-text-rendering: optimizeLegibility;
+  text-rendering: optimizeLegibility;
+}
+
+.new-todo,
+.edit {
+  position: relative;
+  margin: 0;
+  width: 100%;
+  font-size: 24px;
+  font-family: inherit;
+  font-weight: inherit;
+  line-height: 1.4em;
+  color: inherit;
+  padding: 6px;
+  border: 1px solid #999;
+  box-shadow: inset 0 -1px 5px 0 rgba(0, 0, 0, 0.2);
+  box-sizing: border-box;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+.new-todo {
+  padding: 16px 16px 16px 60px;
+  border: none;
+  background: rgba(0, 0, 0, 0.003);
+  box-shadow: inset 0 -2px 1px rgba(0,0,0,0.03);
+}
+
+.main {
+  position: relative;
+  z-index: 2;
+  border-top: 1px solid #e6e6e6;
+}
+
+.toggle-all {
+  width: 1px;
+  height: 1px;
+  border: none; /* Mobile Safari */
+  opacity: 0;
+  position: absolute;
+  right: 100%;
+  bottom: 100%;
+}
+
+.toggle-all + label {
+  width: 60px;
+  height: 34px;
+  font-size: 0;
+  position: absolute;
+  top: -52px;
+  left: -13px;
+  -webkit-transform: rotate(90deg);
+  transform: rotate(90deg);
+}
+
+.toggle-all + label:before {
+  content: '❯';
+  font-size: 22px;
+  color: #e6e6e6;
+  padding: 10px 27px 10px 27px;
+}
+
+.toggle-all:checked + label:before {
+  color: #737373;
+}
+
+.todo-list {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+
+.todo-list li {
+  position: relative;
+  font-size: 24px;
+  border-bottom: 1px solid #ededed;
+}
+
+.todo-list li:last-child {
+  border-bottom: none;
+}
+
+.todo-list li.editing {
+  border-bottom: none;
+  padding: 0;
+}
+
+.todo-list li.editing .edit {
+  display: block;
+  width: calc(100% - 43px);
+  padding: 12px 16px;
+  margin: 0 0 0 43px;
+}
+
+.todo-list li.editing .view {
+  display: none;
+}
+
+.todo-list li .toggle {
+  text-align: center;
+  width: 40px;
+  /* auto, since non-WebKit browsers doesn't support input styling */
+  height: auto;
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  margin: auto 0;
+  border: none; /* Mobile Safari */
+  -webkit-appearance: none;
+  appearance: none;
+}
+
+.todo-list li .toggle {
+  opacity: 0;
+}
+
+.todo-list li .toggle + label {
+  /*
+    Firefox requires `#` to be escaped - https://bugzilla.mozilla.org/show_bug.cgi?id=922433
+    IE and Edge requires *everything* to be escaped to render, so we do that instead of just the `#` - https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/7157459/
+  */
+  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23ededed%22%20stroke-width%3D%223%22/%3E%3C/svg%3E');
+  background-repeat: no-repeat;
+  background-position: center left;
+}
+
+.todo-list li .toggle:checked + label {
+  background-image: url('data:image/svg+xml;utf8,%3Csvg%20xmlns%3D%22http%3A//www.w3.org/2000/svg%22%20width%3D%2240%22%20height%3D%2240%22%20viewBox%3D%22-10%20-18%20100%20135%22%3E%3Ccircle%20cx%3D%2250%22%20cy%3D%2250%22%20r%3D%2250%22%20fill%3D%22none%22%20stroke%3D%22%23bddad5%22%20stroke-width%3D%223%22/%3E%3Cpath%20fill%3D%22%235dc2af%22%20d%3D%22M72%2025L42%2071%2027%2056l-4%204%2020%2020%2034-52z%22/%3E%3C/svg%3E');
+}
+
+.todo-list li label {
+  word-break: break-all;
+  padding: 15px 15px 15px 60px;
+  display: block;
+  line-height: 1.2;
+  transition: color 0.4s;
+  font-weight: 400;
+  color: #4d4d4d;
+}
+
+.todo-list li.completed label {
+  color: #cdcdcd;
+  text-decoration: line-through;
+}
+
+.todo-list li .destroy {
+  display: none;
+  position: absolute;
+  top: 0;
+  right: 10px;
+  bottom: 0;
+  width: 40px;
+  height: 40px;
+  margin: auto 0;
+  font-size: 30px;
+  color: #cc9a9a;
+  margin-bottom: 11px;
+  transition: color 0.2s ease-out;
+}
+
+.todo-list li .destroy:hover {
+  color: #af5b5e;
+}
+
+.todo-list li .destroy:after {
+  content: '×';
+}
+
+.todo-list li:hover .destroy {
+  display: block;
+}
+
+.todo-list li .edit {
+  display: none;
+}
+
+.todo-list li.editing:last-child {
+  margin-bottom: -1px;
+}
+
+.footer {
+  padding: 10px 15px;
+  height: 20px;
+  text-align: center;
+  font-size: 15px;
+  border-top: 1px solid #e6e6e6;
+}
+
+.footer:before {
+  content: '';
+  position: absolute;
+  right: 0;
+  bottom: 0;
+  left: 0;
+  height: 50px;
+  overflow: hidden;
+  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.2),
+  0 8px 0 -3px #f6f6f6,
+  0 9px 1px -3px rgba(0, 0, 0, 0.2),
+  0 16px 0 -6px #f6f6f6,
+  0 17px 2px -6px rgba(0, 0, 0, 0.2);
+}
+
+.todo-count {
+  float: left;
+  text-align: left;
+}
+
+.todo-count strong {
+  font-weight: 300;
+}
+
+.filters {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+  position: absolute;
+  right: 0;
+  left: 0;
+}
+
+.filters li {
+  display: inline;
+}
+
+.filters li a {
+  color: inherit;
+  margin: 3px;
+  padding: 3px 7px;
+  text-decoration: none;
+  border: 1px solid transparent;
+  border-radius: 3px;
+}
+
+.filters li a:hover {
+  border-color: rgba(175, 47, 47, 0.1);
+}
+
+.filters li a.selected {
+  border-color: rgba(175, 47, 47, 0.2);
+}
+
+.clear-completed,
+html .clear-completed:active {
+  float: right;
+  position: relative;
+  line-height: 20px;
+  text-decoration: none;
+  cursor: pointer;
+}
+
+.clear-completed:hover {
+  text-decoration: underline;
+}
+
+.info {
+  margin: 65px auto 0;
+  color: #4d4d4d;
+  font-size: 11px;
+  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
+  text-align: center;
+}
+
+.info p {
+  line-height: 1;
+}
+
+.info a {
+  color: inherit;
+  text-decoration: none;
+  font-weight: 400;
+}
+
+.info a:hover {
+  text-decoration: underline;
+}
+
+/*
+	Hack to remove background from Mobile Safari.
+	Can't use it globally since it destroys checkboxes in Firefox
+*/
+@media screen and (-webkit-min-device-pixel-ratio:0) {
+  .toggle-all,
+  .todo-list li .toggle {
+    background: none;
+  }
+
+  .todo-list li .toggle {
+    height: 40px;
+  }
+}
+
+@media (max-width: 430px) {
+  .footer {
+    height: 50px;
+  }
+
+  .filters {
+    bottom: 10px;
+  }
+}

examples/basic-crud-application/vue-client/src/App.vue

@@ -0,0 +1,123 @@
+<script setup>
+import { computed, ref } from "vue";
+import { useTodoStore } from "@/stores/todo";
+import { socket } from "@/socket";
+
+const newTodo = ref("");
+const editedTodo = ref(undefined);
+const newTitle = ref("");
+
+const store = useTodoStore();
+
+// remove any existing listeners (in case of hot reload)
+socket.off();
+
+store.bindEvents();
+
+function addTodo() {
+  const value = newTodo.value && newTodo.value.trim();
+  if (!value) {
+    return;
+  }
+  store.add(value);
+  newTodo.value = "";
+}
+
+function editTodo(todo) {
+  editedTodo.value = todo;
+  newTitle.value = todo.title;
+}
+
+function doneEdit(todo) {
+  if (newTitle.value) {
+    store.setTitle(todo, newTitle.value);
+  } else {
+    store.delete(todo);
+  }
+  editedTodo.value = undefined;
+}
+
+function cancelEdit() {
+  editedTodo.value = undefined;
+}
+
+const allDone = computed({
+  get: () => {
+    return store.remaining === 0;
+  },
+  set: (value) => {
+    store.toggleAll(value);
+  },
+});
+
+function pluralize(word, count) {
+  return word + (count === 1 ? "" : "s");
+}
+</script>
+
+<template>
+  <section class="todoapp" v-cloak>
+    <header class="header">
+      <h1>todos</h1>
+      <input
+        class="new-todo"
+        autofocus
+        autocomplete="off"
+        placeholder="What needs to be done?"
+        v-model="newTodo"
+        @keydown.enter="addTodo"
+      />
+    </header>
+    <section class="main" v-show="store.todos.length">
+      <input
+        id="toggle-all"
+        class="toggle-all"
+        type="checkbox"
+        v-model="allDone"
+      />
+      <label for="toggle-all">Mark all as complete</label>
+      <ul class="todo-list">
+        <li
+          class="todo"
+          v-for="todo in store.todos"
+          :key="todo.id"
+          :class="{ completed: todo.completed, editing: todo === editedTodo }"
+        >
+          <div class="view">
+            <input
+              class="toggle"
+              type="checkbox"
+              v-model="todo.completed"
+              @click="store.toggleOne(todo)"
+            />
+            <label @dblclick="editTodo(todo)">{{ todo.title }}</label>
+            <button class="destroy" @click="store.delete(todo)"></button>
+          </div>
+          <input
+            class="edit"
+            type="text"
+            v-model="newTitle"
+            @blur="doneEdit"
+            @keydown.enter="doneEdit(todo)"
+            @keydown.esc="cancelEdit(todo)"
+          />
+        </li>
+      </ul>
+    </section>
+    <footer class="footer" v-show="store.todos.length">
+      <span class="todo-count">
+        <strong v-text="store.remaining"></strong>
+        {{ pluralize("item", store.remaining) }} left
+      </span>
+      <button
+        class="clear-completed"
+        @click="store.deleteCompleted"
+        v-show="store.todos.length > store.remaining"
+      >
+        Clear complete
+      </button>
+    </footer>
+  </section>
+</template>
+
+<style scoped></style>

examples/basic-crud-application/vue-client/src/main.js

@@ -0,0 +1,9 @@
+import { createApp } from "vue";
+import { createPinia } from "pinia";
+import App from "./App.vue";
+
+const pinia = createPinia();
+const app = createApp(App);
+
+app.use(pinia);
+app.mount("#app");

examples/basic-crud-application/vue-client/src/socket.js

@@ -0,0 +1,7 @@
+import { io } from "socket.io-client";
+
+// "undefined" means the URL will be computed from the `window.location` object
+const URL =
+  process.env.NODE_ENV === "production" ? undefined : "http://localhost:3000";
+
+export const socket = io(URL);

examples/basic-crud-application/vue-client/src/stores/todo.js

@@ -0,0 +1,106 @@
+import { defineStore } from "pinia";
+import { socket } from "@/socket";
+
+export const useTodoStore = defineStore("todo", {
+  state: () => ({
+    todos: [],
+  }),
+
+  getters: {
+    remaining(state) {
+      let count = 0;
+      state.todos.forEach((todo) => {
+        if (!todo.completed) {
+          count++;
+        }
+      });
+      return count;
+    },
+  },
+
+  actions: {
+    bindEvents() {
+      socket.on("connect", () => {
+        socket.emit("todo:list", (res) => {
+          this.todos = res.data;
+        });
+      });
+
+      socket.on("todo:created", (todo) => {
+        this.todos.push(todo);
+      });
+
+      socket.on("todo:updated", (todo) => {
+        const existingTodo = this.todos.find((t) => {
+          return t.id === todo.id;
+        });
+        if (existingTodo) {
+          existingTodo.title = todo.title;
+          existingTodo.completed = todo.completed;
+        }
+      });
+
+      socket.on("todo:deleted", (id) => {
+        const i = this.todos.findIndex((t) => {
+          return t.id === id;
+        });
+        if (i !== -1) {
+          this.todos.splice(i, 1);
+        }
+      });
+    },
+
+    add(title) {
+      const todo = {
+        id: Date.now(),
+        title,
+        completed: false,
+      };
+      this.todos.push(todo);
+      socket.emit("todo:create", { title, completed: false }, (res) => {
+        todo.id = res.data;
+      });
+    },
+
+    setTitle(todo, title) {
+      todo.title = title;
+      socket.emit("todo:update", todo, () => {});
+    },
+
+    delete(todo) {
+      const i = this.todos.findIndex((t) => {
+        return t.id === todo.id;
+      });
+
+      if (i !== -1) {
+        this.todos.splice(i, 1);
+        socket.emit("todo:delete", todo.id, () => {});
+      }
+    },
+
+    deleteCompleted() {
+      this.todos.forEach((todo) => {
+        if (todo.completed) {
+          socket.emit("todo:delete", todo.id, () => {});
+        }
+      });
+
+      this.todos = this.todos.filter((t) => {
+        return !t.completed;
+      });
+    },
+
+    toggleOne(todo) {
+      todo.completed = !todo.completed;
+      socket.emit("todo:update", todo, () => {});
+    },
+
+    toggleAll(onlyActive) {
+      this.todos.forEach((todo) => {
+        if (!onlyActive || !todo.completed) {
+          this.toggleOne(todo);
+        }
+      });
+    },
+  },
+});

examples/basic-crud-application/vue-client/vue.config.js

@@ -0,0 +1,4 @@
+const { defineConfig } = require('@vue/cli-service')
+module.exports = defineConfig({
+  transpileDependencies: true
+})

examples/connection-state-recovery-example/README.md

@@ -0,0 +1,25 @@
+# Example with connection state recovery
+
+This example shows how to use the [Connection state recovery feature](https://socket.io/docs/v4/connection-state-recovery).
+
+![Video of the example](assets/csr.gif)
+
+## How to use
+
+```shell
+# choose your module syntax (either ES modules or CommonJS)
+$ cd esm/
+
+# install the dependencies
+$ npm i
+
+# start the server
+$ node index.js
+```
+
+And point your browser to `http://localhost:3000`.
+
+You can also run this example directly in your browser on:
+
+- [CodeSandbox](https://codesandbox.io/p/sandbox/github/socketio/socket.io/tree/main/examples/connection-state-recovery-example/esm?file=index.js)
+- [StackBlitz](https://stackblitz.com/github/socketio/socket.io/tree/main/examples/connection-state-recovery-example/esm?file=index.js)

examples/connection-state-recovery-example/cjs/.codesandbox/Dockerfile

@@ -0,0 +1 @@
+FROM node:20-bullseye

examples/connection-state-recovery-example/cjs/.codesandbox/tasks.json

@@ -0,0 +1,18 @@
+{
+  // These tasks will run in order when initializing your CodeSandbox project.
+  "setupTasks": [
+    {
+      "name": "Install Dependencies",
+      "command": "npm install"
+    }
+  ],
+
+  // These tasks can be run from CodeSandbox. Running one will open a log in the app.
+  "tasks": {
+    "npm start": {
+      "name": "npm start",
+      "command": "npm start",
+      "runAtStart": true
+    }
+  }
+}

examples/connection-state-recovery-example/cjs/index.html

@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Connection state recovery | Socket.IO</title>
+  </head>
+  <body>
+    <p>Status: <span id="connectionStatus">disconnected</span></p>
+    <p>Recovered? <span id="recoveryStatus">-</span></p>
+
+    <p>Latest messages:</p>
+    <ul id="messages"></ul>
+
+    <script src="/socket.io/socket.io.js"></script>
+    <script>
+      const $connectionStatus = document.getElementById("connectionStatus");
+      const $recoveryStatus = document.getElementById("recoveryStatus");
+      const $messages = document.getElementById("messages");
+
+      const socket = io({
+        reconnectionDelay: 5000 // 1000 by default
+      });
+
+      socket.on("connect", () => {
+        $connectionStatus.innerText = "connected";
+        $recoveryStatus.innerText = "" + socket.recovered;
+
+        setTimeout(() => {
+          // close the low-level connection and trigger a reconnection
+          socket.io.engine.close();
+        }, Math.random() * 5000 + 1000);
+      });
+
+      socket.on("disconnect", () => {
+        $connectionStatus.innerText = "disconnected";
+        $recoveryStatus.innerText = "-"
+      });
+
+      socket.on("ping", (value) => {
+        const item = document.createElement("li");
+        item.textContent = value;
+        $messages.prepend(item);
+        if ($messages.childElementCount > 10) {
+          $messages.removeChild($messages.lastChild);
+        }
+      });
+    </script>
+  </body>
+</html>

examples/connection-state-recovery-example/cjs/index.js

@@ -0,0 +1,53 @@
+const { readFile } = require("node:fs/promises");
+const { createServer } = require("node:http");
+const { Server } = require("socket.io");
+
+const httpServer = createServer(async (req, res) => {
+  if (req.url !== "/") {
+    res.writeHead(404);
+    res.end("Not found");
+    return;
+  }
+  // reload the file every time
+  const content = await readFile("index.html");
+  const length = Buffer.byteLength(content);
+
+  res.writeHead(200, {
+    "Content-Type": "text/html",
+    "Content-Length": length,
+  });
+  res.end(content);
+});
+
+const io = new Server(httpServer, {
+  connectionStateRecovery: {
+    // the backup duration of the sessions and the packets
+    maxDisconnectionDuration: 2 * 60 * 1000,
+    // whether to skip middlewares upon successful recovery
+    skipMiddlewares: true,
+  },
+});
+
+io.on("connection", (socket) => {
+  console.log(`connect ${socket.id}`);
+
+  if (socket.recovered) {
+    console.log("recovered!");
+    console.log("socket.rooms:", socket.rooms);
+    console.log("socket.data:", socket.data);
+  } else {
+    console.log("new connection");
+    socket.join("sample room");
+    socket.data.foo = "bar";
+  }
+
+  socket.on("disconnect", (reason) => {
+    console.log(`disconnect ${socket.id} due to ${reason}`);
+  });
+});
+
+setInterval(() => {
+  io.emit("ping", new Date().toISOString());
+}, 1000);
+
+httpServer.listen(3000);

examples/connection-state-recovery-example/cjs/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "connection-state-recovery-example",
+  "version": "0.0.1",
+  "private": true,
+  "type": "commonjs",
+  "description": "Example with connection state recovery",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "socket.io": "^4.7.2"
+  }
+}

examples/connection-state-recovery-example/esm/.codesandbox/Dockerfile

@@ -0,0 +1 @@
+FROM node:20-bullseye

examples/connection-state-recovery-example/esm/.codesandbox/tasks.json

@@ -0,0 +1,18 @@
+{
+  // These tasks will run in order when initializing your CodeSandbox project.
+  "setupTasks": [
+    {
+      "name": "Install Dependencies",
+      "command": "npm install"
+    }
+  ],
+
+  // These tasks can be run from CodeSandbox. Running one will open a log in the app.
+  "tasks": {
+    "npm start": {
+      "name": "npm start",
+      "command": "npm start",
+      "runAtStart": true
+    }
+  }
+}

examples/connection-state-recovery-example/esm/index.html

@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Connection state recovery | Socket.IO</title>
+  </head>
+  <body>
+    <p>Status: <span id="connectionStatus">disconnected</span></p>
+    <p>Recovered? <span id="recoveryStatus">-</span></p>
+
+    <p>Latest messages:</p>
+    <ul id="messages"></ul>
+
+    <script src="/socket.io/socket.io.js"></script>
+    <script>
+      const $connectionStatus = document.getElementById("connectionStatus");
+      const $recoveryStatus = document.getElementById("recoveryStatus");
+      const $messages = document.getElementById("messages");
+
+      const socket = io({
+        reconnectionDelay: 5000 // 1000 by default
+      });
+
+      socket.on("connect", () => {
+        $connectionStatus.innerText = "connected";
+        $recoveryStatus.innerText = "" + socket.recovered;
+
+        setTimeout(() => {
+          // close the low-level connection and trigger a reconnection
+          socket.io.engine.close();
+        }, Math.random() * 5000 + 1000);
+      });
+
+      socket.on("disconnect", () => {
+        $connectionStatus.innerText = "disconnected";
+        $recoveryStatus.innerText = "-"
+      });
+
+      socket.on("ping", (value) => {
+        const item = document.createElement("li");
+        item.textContent = value;
+        $messages.prepend(item);
+        if ($messages.childElementCount > 10) {
+          $messages.removeChild($messages.lastChild);
+        }
+      });
+    </script>
+  </body>
+</html>

examples/connection-state-recovery-example/esm/index.js

@@ -0,0 +1,53 @@
+import { readFile } from "node:fs/promises";
+import { createServer } from "node:http";
+import { Server } from "socket.io";
+
+const httpServer = createServer(async (req, res) => {
+  if (req.url !== "/") {
+    res.writeHead(404);
+    res.end("Not found");
+    return;
+  }
+  // reload the file every time
+  const content = await readFile("index.html");
+  const length = Buffer.byteLength(content);
+
+  res.writeHead(200, {
+    "Content-Type": "text/html",
+    "Content-Length": length,
+  });
+  res.end(content);
+});
+
+const io = new Server(httpServer, {
+  connectionStateRecovery: {
+    // the backup duration of the sessions and the packets
+    maxDisconnectionDuration: 2 * 60 * 1000,
+    // whether to skip middlewares upon successful recovery
+    skipMiddlewares: true,
+  },
+});
+
+io.on("connection", (socket) => {
+  console.log(`connect ${socket.id}`);
+
+  if (socket.recovered) {
+    console.log("recovered!");
+    console.log("socket.rooms:", socket.rooms);
+    console.log("socket.data:", socket.data);
+  } else {
+    console.log("new connection");
+    socket.join("sample room");
+    socket.data.foo = "bar";
+  }
+
+  socket.on("disconnect", (reason) => {
+    console.log(`disconnect ${socket.id} due to ${reason}`);
+  });
+});
+
+setInterval(() => {
+  io.emit("ping", new Date().toISOString());
+}, 1000);
+
+httpServer.listen(3000);

examples/connection-state-recovery-example/esm/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "connection-state-recovery-example",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "description": "Example with connection state recovery",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "socket.io": "^4.7.2"
+  }
+}

examples/es-modules/server.js

@@ -2,7 +2,7 @@ import { Server } from "socket.io";
 
 const io = new Server(8080);
 
-io.on("connect", (socket) => {
+io.on("connection", (socket) => {
   console.log(`connect ${socket.id}`);
 
   socket.on("ping", (cb) => {

examples/express-session-example/cjs/index.html

@@ -52,6 +52,10 @@
       socket.on("disconnect", () => {
         ioStatus.innerText = "disconnected";
       });
+
+      socket.on("current count", (count) => {
+        ioCount.innerText = count;
+      });
     </script>
   </body>
 </html>

examples/express-session-example/cjs/index.js

@@ -0,0 +1,66 @@
+const express = require("express");
+const { createServer } = require("node:http");
+const { join } = require("node:path");
+const { Server } = require("socket.io");
+const session = require("express-session");
+
+const port = process.env.PORT || 3000;
+
+const app = express();
+const httpServer = createServer(app);
+
+const sessionMiddleware = session({
+  secret: "changeit",
+  resave: true,
+  saveUninitialized: true,
+});
+
+app.use(sessionMiddleware);
+
+app.get("/", (req, res) => {
+  res.sendFile(join(__dirname, "index.html"));
+});
+
+app.post("/incr", (req, res) => {
+  const session = req.session;
+  session.count = (session.count || 0) + 1;
+  res.status(200).end("" + session.count);
+
+  io.to(session.id).emit("current count", session.count);
+});
+
+app.post("/logout", (req, res) => {
+  const sessionId = req.session.id;
+  req.session.destroy(() => {
+    // disconnect all Socket.IO connections linked to this session ID
+    io.to(sessionId).disconnectSockets();
+    res.status(204).end();
+  });
+});
+
+const io = new Server(httpServer);
+
+io.engine.use(sessionMiddleware);
+
+io.on("connection", (socket) => {
+  const req = socket.request;
+
+  socket.join(req.session.id);
+
+  socket.on("incr", (cb) => {
+    req.session.reload((err) => {
+      if (err) {
+        // session has expired
+        return socket.disconnect();
+      }
+      req.session.count = (req.session.count || 0) + 1;
+      req.session.save(() => {
+        cb(req.session.count);
+      });
+    });
+  });
+});
+
+httpServer.listen(port, () => {
+  console.log(`application is running at: http://localhost:${port}`);
+});

examples/express-session-example/cjs/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "express-session-example",
+  "version": "0.0.1",
+  "private": true,
+  "type": "commonjs",
+  "description": "Example with express-session (https://github.com/expressjs/session)",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "express": "~4.17.3",
+    "express-session": "~1.17.2",
+    "socket.io": "^4.7.2"
+  }
+}

examples/express-session-example/esm/index.html

@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Example with express-session</title>
+  </head>
+  <body>
+    <button onclick="incrementWithFetch()">Increment with fetch()</button>
+    <button onclick="logout()">Logout</button>
+    <p>Count: <span id="httpCount">0</span></p>
+
+    <button onclick="incrementWithEmit()">
+      Increment with Socket.IO emit()
+    </button>
+    <p>Status: <span id="ioStatus">disconnected</span></p>
+    <p>Count: <span id="ioCount">0</span></p>
+
+    <script src="/socket.io/socket.io.js"></script>
+    <script>
+      const httpCount = document.getElementById("httpCount");
+      const ioStatus = document.getElementById("ioStatus");
+      const ioCount = document.getElementById("ioCount");
+
+      const socket = io({
+        // with WebSocket only
+        // transports: ["websocket"],
+      });
+
+      async function incrementWithFetch() {
+        const response = await fetch("/incr", {
+          method: "post",
+        });
+        httpCount.innerText = await response.text();
+      }
+
+      function logout() {
+        fetch("/logout", {
+          method: "post",
+        });
+      }
+
+      async function incrementWithEmit() {
+        socket.emit("incr", (count) => {
+          ioCount.innerText = count;
+        });
+      }
+
+      socket.on("connect", () => {
+        ioStatus.innerText = "connected";
+      });
+
+      socket.on("disconnect", () => {
+        ioStatus.innerText = "disconnected";
+      });
+
+      socket.on("current count", (count) => {
+        ioCount.innerText = count;
+      });
+    </script>
+  </body>
+</html>

examples/express-session-example/esm/index.js

@@ -1,5 +1,5 @@
 import express from "express";
-import { createServer } from "http";
+import { createServer } from "node:http";
 import { Server } from "socket.io";
 import session from "express-session";
 
@@ -17,13 +17,15 @@ const sessionMiddleware = session({
 app.use(sessionMiddleware);
 
 app.get("/", (req, res) => {
-  res.sendFile("./index.html", { root: process.cwd() });
+  res.sendFile(new URL("./index.html", import.meta.url).pathname);
 });
 
 app.post("/incr", (req, res) => {
   const session = req.session;
   session.count = (session.count || 0) + 1;
   res.status(200).end("" + session.count);
+
+  io.to(session.id).emit("current count", session.count);
 });
 
 app.post("/logout", (req, res) => {
@@ -35,39 +37,11 @@ app.post("/logout", (req, res) => {
   });
 });
 
-const io = new Server(httpServer, {
-  allowRequest: (req, callback) => {
-    // with HTTP long-polling, we have access to the HTTP response here, but this is not
-    // the case with WebSocket, so we provide a dummy response object
-    const fakeRes = {
-      getHeader() {
-        return [];
-      },
-      setHeader(key, values) {
-        req.cookieHolder = values[0];
-      },
-      writeHead() {},
-    };
-    sessionMiddleware(req, fakeRes, () => {
-      if (req.session) {
-        // trigger the setHeader() above
-        fakeRes.writeHead();
-        // manually save the session (normally triggered by res.end())
-        req.session.save();
-      }
-      callback(null, true);
-    });
-  },
-});
+const io = new Server(httpServer);
 
-io.engine.on("initial_headers", (headers, req) => {
-  if (req.cookieHolder) {
-    headers["set-cookie"] = req.cookieHolder;
-    delete req.cookieHolder;
-  }
-});
+io.engine.use(sessionMiddleware);
 
-io.on("connect", (socket) => {
+io.on("connection", (socket) => {
   const req = socket.request;
 
   socket.join(req.session.id);

examples/express-session-example/esm/package.json

@@ -10,6 +10,6 @@
   "dependencies": {
     "express": "~4.17.3",
     "express-session": "~1.17.2",
-    "socket.io": "~4.4.1"
+    "socket.io": "^4.7.2"
   }
 }

examples/express-session-example/ts/index.html

@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Example with express-session</title>
+  </head>
+  <body>
+    <button onclick="incrementWithFetch()">Increment with fetch()</button>
+    <button onclick="logout()">Logout</button>
+    <p>Count: <span id="httpCount">0</span></p>
+
+    <button onclick="incrementWithEmit()">
+      Increment with Socket.IO emit()
+    </button>
+    <p>Status: <span id="ioStatus">disconnected</span></p>
+    <p>Count: <span id="ioCount">0</span></p>
+
+    <script src="/socket.io/socket.io.js"></script>
+    <script>
+      const httpCount = document.getElementById("httpCount");
+      const ioStatus = document.getElementById("ioStatus");
+      const ioCount = document.getElementById("ioCount");
+
+      const socket = io({
+        // with WebSocket only
+        // transports: ["websocket"],
+      });
+
+      async function incrementWithFetch() {
+        const response = await fetch("/incr", {
+          method: "post",
+        });
+        httpCount.innerText = await response.text();
+      }
+
+      function logout() {
+        fetch("/logout", {
+          method: "post",
+        });
+      }
+
+      async function incrementWithEmit() {
+        socket.emit("incr", (count) => {
+          ioCount.innerText = count;
+        });
+      }
+
+      socket.on("connect", () => {
+        ioStatus.innerText = "connected";
+      });
+
+      socket.on("disconnect", () => {
+        ioStatus.innerText = "disconnected";
+      });
+
+      socket.on("current count", (count) => {
+        ioCount.innerText = count;
+      });
+    </script>
+  </body>
+</html>

examples/express-session-example/ts/index.ts

@@ -0,0 +1,72 @@
+import express = require("express");
+import { createServer } from "http";
+import { Server } from "socket.io";
+import session from "express-session";
+import { type Request } from "express";
+
+declare module "express-session" {
+  interface SessionData {
+    count: number;
+  }
+}
+
+const port = process.env.PORT || 3000;
+
+const app = express();
+const httpServer = createServer(app);
+
+const sessionMiddleware = session({
+  secret: "changeit",
+  resave: true,
+  saveUninitialized: true,
+});
+
+app.use(sessionMiddleware);
+
+app.get("/", (req, res) => {
+  res.sendFile(new URL("./index.html", import.meta.url).pathname);
+});
+
+app.post("/incr", (req, res) => {
+  const session = req.session;
+  session.count = (session.count || 0) + 1;
+  res.status(200).end("" + session.count);
+
+  io.to(session.id).emit("current count", session.count);
+});
+
+app.post("/logout", (req, res) => {
+  const sessionId = req.session.id;
+  req.session.destroy(() => {
+    // disconnect all Socket.IO connections linked to this session ID
+    io.to(sessionId).disconnectSockets();
+    res.status(204).end();
+  });
+});
+
+const io = new Server(httpServer);
+
+io.engine.use(sessionMiddleware);
+
+io.on("connection", (socket) => {
+  const req = socket.request as Request;
+
+  socket.join(req.session.id);
+
+  socket.on("incr", (cb) => {
+    req.session.reload((err) => {
+      if (err) {
+        // session has expired
+        return socket.disconnect();
+      }
+      req.session.count = (req.session.count || 0) + 1;
+      req.session.save(() => {
+        cb(req.session.count);
+      });
+    });
+  });
+});
+
+httpServer.listen(port, () => {
+  console.log(`application is running at: http://localhost:${port}`);
+});

examples/express-session-example/ts/package.json

@@ -0,0 +1,20 @@
+{
+  "name": "express-session-example",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "description": "Example with express-session (https://github.com/expressjs/session)",
+  "scripts": {
+    "start": "ts-node index.ts"
+  },
+  "dependencies": {
+    "@types/express": "^4.17.17",
+    "@types/express-session": "^1.17.7",
+    "@types/node": "^20.6.0",
+    "express": "~4.17.3",
+    "express-session": "~1.17.2",
+    "socket.io": "^4.7.2",
+    "ts-node": "^10.9.1",
+    "typescript": "^5.2.2"
+  }
+}

examples/express-session-example/ts/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "target": "ES2022",
+    "strict": true
+  },
+  "ts-node": {
+    "esm": true
+  }
+}

examples/typescript/server.ts

@@ -2,7 +2,7 @@ import { Server } from "socket.io";
 
 const io = new Server(8080);
 
-io.on("connect", (socket) => {
+io.on("connection", (socket) => {
     console.log(`connect ${socket.id}`);
 
     socket.on("ping", (cb) => {

lib/broadcast-operator.ts

@@ -8,10 +8,10 @@ import type {
   EventsMap,
   TypedEventBroadcaster,
   DecorateAcknowledgements,
-  DecorateAcknowledgementsWithTimeoutAndMultipleResponses,
   AllButLast,
   Last,
-  SecondArg,
+  FirstNonErrorArg,
+  EventNamesWithError,
 } from "./typed-events";
 
 export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
@@ -177,7 +177,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
   public timeout(timeout: number) {
     const flags = Object.assign({}, this.flags, { timeout });
     return new BroadcastOperator<
-      DecorateAcknowledgementsWithTimeoutAndMultipleResponses<EmitEvents>,
+      DecorateAcknowledgements<EmitEvents>,
       SocketData
     >(this.adapter, this.rooms, this.exceptRooms, flags);
   }
@@ -254,7 +254,7 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
         clearTimeout(timer);
         ack.apply(this, [
           null,
-          this.flags.expectSingleResponse ? null : responses,
+          this.flags.expectSingleResponse ? responses[0] : responses,
         ]);
       }
     };
@@ -300,10 +300,10 @@ export class BroadcastOperator<EmitEvents extends EventsMap, SocketData>
    *
    * @return a Promise that will be fulfilled when all clients have acknowledged the event
    */
-  public emitWithAck<Ev extends EventNames<EmitEvents>>(
+  public emitWithAck<Ev extends EventNamesWithError<EmitEvents>>(
     ev: Ev,
     ...args: AllButLast<EventParams<EmitEvents, Ev>>
-  ): Promise<SecondArg<Last<EventParams<EmitEvents, Ev>>>> {
+  ): Promise<FirstNonErrorArg<Last<EventParams<EmitEvents, Ev>>>> {
     return new Promise((resolve, reject) => {
       args.push((err, responses) => {
         if (err) {
@@ -516,11 +516,10 @@ export class RemoteSocket<EmitEvents extends EventsMap, SocketData>
    *
    * @param timeout
    */
-  public timeout(timeout: number) {
-    return this.operator.timeout(timeout) as BroadcastOperator<
-      DecorateAcknowledgements<EmitEvents>,
-      SocketData
-    >;
+  public timeout(
+    timeout: number
+  ): BroadcastOperator<DecorateAcknowledgements<EmitEvents>, SocketData> {
+    return this.operator.timeout(timeout);
   }
 
   public emit<Ev extends EventNames<EmitEvents>>(

lib/index.ts

@@ -1,6 +1,6 @@
 import http = require("http");
 import type { Server as HTTPSServer } from "https";
-import type { Http2SecureServer } from "http2";
+import type { Http2SecureServer, Http2Server } from "http2";
 import { createReadStream } from "fs";
 import { createDeflate, createGzip, createBrotliCompress } from "zlib";
 import accepts = require("accepts");
@@ -36,8 +36,9 @@ import {
   DecorateAcknowledgementsWithTimeoutAndMultipleResponses,
   AllButLast,
   Last,
-  FirstArg,
-  SecondArg,
+  RemoveAcknowledgements,
+  EventNamesWithAck,
+  FirstNonErrorArg,
 } from "./typed-events";
 import { patchAdapter, restoreAdapter, serveFile } from "./uws";
 import corsMiddleware from "cors";
@@ -55,6 +56,12 @@ type ParentNspNameMatchFn = (
 
 type AdapterConstructor = typeof Adapter | ((nsp: Namespace) => Adapter);
 
+type TServerInstance =
+  | http.Server
+  | HTTPSServer
+  | Http2SecureServer
+  | Http2Server;
+
 interface ServerOptions extends EngineOptions, AttachOptions {
   /**
    * name of the path to capture
@@ -140,7 +147,7 @@ export class Server<
   SocketData = any
 > extends StrictEventEmitter<
   ServerSideEvents,
-  EmitEvents,
+  RemoveAcknowledgements<EmitEvents>,
   ServerReservedEventsMap<
     ListenEvents,
     EmitEvents,
@@ -202,7 +209,7 @@ export class Server<
    * @private
    */
   _connectTimeout: number;
-  private httpServer: http.Server | HTTPSServer | Http2SecureServer;
+  private httpServer: TServerInstance;
   private _corsMiddleware: (
     req: http.IncomingMessage,
     res: http.ServerResponse,
@@ -216,28 +223,13 @@ export class Server<
    * @param [opts]
    */
   constructor(opts?: Partial<ServerOptions>);
+  constructor(srv?: TServerInstance | number, opts?: Partial<ServerOptions>);
   constructor(
-    srv?: http.Server | HTTPSServer | Http2SecureServer | number,
+    srv: undefined | Partial<ServerOptions> | TServerInstance | number,
     opts?: Partial<ServerOptions>
   );
   constructor(
-    srv:
-      | undefined
-      | Partial<ServerOptions>
-      | http.Server
-      | HTTPSServer
-      | Http2SecureServer
-      | number,
-    opts?: Partial<ServerOptions>
-  );
-  constructor(
-    srv:
-      | undefined
-      | Partial<ServerOptions>
-      | http.Server
-      | HTTPSServer
-      | Http2SecureServer
-      | number,
+    srv: undefined | Partial<ServerOptions> | TServerInstance | number,
     opts: Partial<ServerOptions> = {}
   ) {
     super();
@@ -270,9 +262,7 @@ export class Server<
     opts.cleanupEmptyChildNamespaces = !!opts.cleanupEmptyChildNamespaces;
     this.sockets = this.of("/");
     if (srv || typeof srv == "number")
-      this.attach(
-        srv as http.Server | HTTPSServer | Http2SecureServer | number
-      );
+      this.attach(srv as TServerInstance | number);
 
     if (this.opts.cors) {
       this._corsMiddleware = corsMiddleware(this.opts.cors);
@@ -406,7 +396,7 @@ export class Server<
    * @return self
    */
   public listen(
-    srv: http.Server | HTTPSServer | Http2SecureServer | number,
+    srv: TServerInstance | number,
     opts: Partial<ServerOptions> = {}
   ): this {
     return this.attach(srv, opts);
@@ -420,7 +410,7 @@ export class Server<
    * @return self
    */
   public attach(
-    srv: http.Server | HTTPSServer | Http2SecureServer | number,
+    srv: TServerInstance | number,
     opts: Partial<ServerOptions> = {}
   ): this {
     if ("function" == typeof srv) {
@@ -526,7 +516,7 @@ export class Server<
    * @private
    */
   private initEngine(
-    srv: http.Server | HTTPSServer | Http2SecureServer,
+    srv: TServerInstance,
     opts: EngineOptions & AttachOptions
   ): void {
     // initialize engine
@@ -549,9 +539,7 @@ export class Server<
    * @param srv http server
    * @private
    */
-  private attachServe(
-    srv: http.Server | HTTPSServer | Http2SecureServer
-  ): void {
+  private attachServe(srv: TServerInstance): void {
     debug("attaching client serving req handler");
 
     const evs = srv.listeners("request").slice(0);
@@ -846,26 +834,6 @@ export class Server<
     return this.sockets.except(room);
   }
 
-  /**
-   * Emits an event and waits for an acknowledgement from all clients.
-   *
-   * @example
-   * try {
-   *   const responses = await io.timeout(1000).emitWithAck("some-event");
-   *   console.log(responses); // one response per client
-   * } catch (e) {
-   *   // some clients did not acknowledge the event in the given delay
-   * }
-   *
-   * @return a Promise that will be fulfilled when all clients have acknowledged the event
-   */
-  public emitWithAck<Ev extends EventNames<EmitEvents>>(
-    ev: Ev,
-    ...args: AllButLast<EventParams<EmitEvents, Ev>>
-  ): Promise<SecondArg<Last<EventParams<EmitEvents, Ev>>>> {
-    return this.sockets.emitWithAck(ev, ...args);
-  }
-
   /**
    * Sends a `message` event to all clients.
    *
@@ -882,7 +850,9 @@ export class Server<
    * @return self
    */
   public send(...args: EventParams<EmitEvents, "message">): this {
-    this.sockets.emit("message", ...args);
+    // This type-cast is needed because EmitEvents likely doesn't have `message` as a key.
+    // if you specify the EmitEvents, the type of args will be never.
+    this.sockets.emit("message" as any, ...args);
     return this;
   }
 
@@ -892,7 +862,9 @@ export class Server<
    * @return self
    */
   public write(...args: EventParams<EmitEvents, "message">): this {
-    this.sockets.emit("message", ...args);
+    // This type-cast is needed because EmitEvents likely doesn't have `message` as a key.
+    // if you specify the EmitEvents, the type of args will be never.
+    this.sockets.emit("message" as any, ...args);
     return this;
   }
 
@@ -948,10 +920,10 @@ export class Server<
    *
    * @return a Promise that will be fulfilled when all servers have acknowledged the event
    */
-  public serverSideEmitWithAck<Ev extends EventNames<ServerSideEvents>>(
+  public serverSideEmitWithAck<Ev extends EventNamesWithAck<ServerSideEvents>>(
     ev: Ev,
     ...args: AllButLast<EventParams<ServerSideEvents, Ev>>
-  ): Promise<FirstArg<Last<EventParams<ServerSideEvents, Ev>>>[]> {
+  ): Promise<FirstNonErrorArg<Last<EventParams<ServerSideEvents, Ev>>>[]> {
     return this.sockets.serverSideEmitWithAck(ev, ...args);
   }
 

lib/namespace.ts

@@ -9,8 +9,12 @@ import {
   DecorateAcknowledgementsWithTimeoutAndMultipleResponses,
   AllButLast,
   Last,
-  FirstArg,
-  SecondArg,
+  DecorateAcknowledgementsWithMultipleResponses,
+  DecorateAcknowledgements,
+  RemoveAcknowledgements,
+  EventNamesWithAck,
+  FirstNonErrorArg,
+  EventNamesWithoutAck,
 } from "./typed-events";
 import type { Client } from "./client";
 import debugModule from "debug";
@@ -117,7 +121,7 @@ export class Namespace<
   SocketData = any
 > extends StrictEventEmitter<
   ServerSideEvents,
-  EmitEvents,
+  RemoveAcknowledgements<EmitEvents>,
   NamespaceReservedEventsMap<
     ListenEvents,
     EmitEvents,
@@ -252,7 +256,10 @@ export class Namespace<
    * @return a new {@link BroadcastOperator} instance for chaining
    */
   public to(room: Room | Room[]) {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).to(room);
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).to(room);
   }
 
   /**
@@ -268,7 +275,10 @@ export class Namespace<
    * @return a new {@link BroadcastOperator} instance for chaining
    */
   public in(room: Room | Room[]) {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).in(room);
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).in(room);
   }
 
   /**
@@ -290,9 +300,10 @@ export class Namespace<
    * @return a new {@link BroadcastOperator} instance for chaining
    */
   public except(room: Room | Room[]) {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).except(
-      room
-    );
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).except(room);
   }
 
   /**
@@ -430,7 +441,7 @@ export class Namespace<
    *
    * @return Always true
    */
-  public emit<Ev extends EventNames<EmitEvents>>(
+  public emit<Ev extends EventNamesWithoutAck<EmitEvents>>(
     ev: Ev,
     ...args: EventParams<EmitEvents, Ev>
   ): boolean {
@@ -440,30 +451,6 @@ export class Namespace<
     );
   }
 
-  /**
-   * Emits an event and waits for an acknowledgement from all clients.
-   *
-   * @example
-   * const myNamespace = io.of("/my-namespace");
-   *
-   * try {
-   *   const responses = await myNamespace.timeout(1000).emitWithAck("some-event");
-   *   console.log(responses); // one response per client
-   * } catch (e) {
-   *   // some clients did not acknowledge the event in the given delay
-   * }
-   *
-   * @return a Promise that will be fulfilled when all clients have acknowledged the event
-   */
-  public emitWithAck<Ev extends EventNames<EmitEvents>>(
-    ev: Ev,
-    ...args: AllButLast<EventParams<EmitEvents, Ev>>
-  ): Promise<SecondArg<Last<EventParams<EmitEvents, Ev>>>> {
-    return new BroadcastOperator<EmitEvents, SocketData>(
-      this.adapter
-    ).emitWithAck(ev, ...args);
-  }
-
   /**
    * Sends a `message` event to all clients.
    *
@@ -482,7 +469,9 @@ export class Namespace<
    * @return self
    */
   public send(...args: EventParams<EmitEvents, "message">): this {
-    this.emit("message", ...args);
+    // This type-cast is needed because EmitEvents likely doesn't have `message` as a key.
+    // if you specify the EmitEvents, the type of args will be never.
+    this.emit("message" as any, ...args);
     return this;
   }
 
@@ -492,7 +481,9 @@ export class Namespace<
    * @return self
    */
   public write(...args: EventParams<EmitEvents, "message">): this {
-    this.emit("message", ...args);
+    // This type-cast is needed because EmitEvents likely doesn't have `message` as a key.
+    // if you specify the EmitEvents, the type of args will be never.
+    this.emit("message" as any, ...args);
     return this;
   }
 
@@ -557,10 +548,10 @@ export class Namespace<
    *
    * @return a Promise that will be fulfilled when all servers have acknowledged the event
    */
-  public serverSideEmitWithAck<Ev extends EventNames<ServerSideEvents>>(
+  public serverSideEmitWithAck<Ev extends EventNamesWithAck<ServerSideEvents>>(
     ev: Ev,
     ...args: AllButLast<EventParams<ServerSideEvents, Ev>>
-  ): Promise<FirstArg<Last<EventParams<ServerSideEvents, Ev>>>[]> {
+  ): Promise<FirstNonErrorArg<Last<EventParams<ServerSideEvents, Ev>>>[]> {
     return new Promise((resolve, reject) => {
       args.push((err, responses) => {
         if (err) {
@@ -612,9 +603,10 @@ export class Namespace<
    * @return self
    */
   public compress(compress: boolean) {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).compress(
-      compress
-    );
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).compress(compress);
   }
 
   /**
@@ -630,7 +622,10 @@ export class Namespace<
    * @return self
    */
   public get volatile() {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).volatile;
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).volatile;
   }
 
   /**
@@ -645,7 +640,10 @@ export class Namespace<
    * @return a new {@link BroadcastOperator} instance for chaining
    */
   public get local() {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).local;
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).local;
   }
 
   /**
@@ -665,9 +663,10 @@ export class Namespace<
    * @param timeout
    */
   public timeout(timeout: number) {
-    return new BroadcastOperator<EmitEvents, SocketData>(this.adapter).timeout(
-      timeout
-    );
+    return new BroadcastOperator<
+      DecorateAcknowledgementsWithMultipleResponses<EmitEvents>,
+      SocketData
+    >(this.adapter).timeout(timeout);
   }
 
   /**

lib/parent-namespace.ts

@@ -2,9 +2,9 @@ import { Namespace } from "./namespace";
 import type { Server, RemoteSocket } from "./index";
 import type {
   EventParams,
-  EventNames,
   EventsMap,
   DefaultEventsMap,
+  EventNamesWithoutAck,
 } from "./typed-events";
 import type { BroadcastOptions } from "socket.io-adapter";
 import debugModule from "debug";
@@ -56,7 +56,7 @@ export class ParentNamespace<
     this.adapter = { broadcast };
   }
 
-  public emit<Ev extends EventNames<EmitEvents>>(
+  public emit<Ev extends EventNamesWithoutAck<EmitEvents>>(
     ev: Ev,
     ...args: EventParams<EmitEvents, Ev>
   ): boolean {

lib/socket.ts

@@ -7,9 +7,10 @@ import {
   DecorateAcknowledgementsWithMultipleResponses,
   DefaultEventsMap,
   EventNames,
+  EventNamesWithAck,
   EventParams,
   EventsMap,
-  FirstArg,
+  FirstNonErrorArg,
   Last,
   StrictEventEmitter,
 } from "./typed-events";
@@ -383,10 +384,10 @@ export class Socket<
    *
    * @return a Promise that will be fulfilled when the client acknowledges the event
    */
-  public emitWithAck<Ev extends EventNames<EmitEvents>>(
+  public emitWithAck<Ev extends EventNamesWithAck<EmitEvents>>(
     ev: Ev,
     ...args: AllButLast<EventParams<EmitEvents, Ev>>
-  ): Promise<FirstArg<Last<EventParams<EmitEvents, Ev>>>> {
+  ): Promise<FirstNonErrorArg<Last<EventParams<EmitEvents, Ev>>>> {
     // the timeout flag is optional
     const withErr = this.flags.timeout !== undefined;
     return new Promise((resolve, reject) => {

lib/typed-events.ts

@@ -1,5 +1,4 @@
 import { EventEmitter } from "events";
-
 /**
  * An events map is an interface that maps event names to their value, which
  * represents the type of the `on` listener.
@@ -21,6 +20,64 @@ export interface DefaultEventsMap {
  */
 export type EventNames<Map extends EventsMap> = keyof Map & (string | symbol);
 
+/**
+ * Returns a union type containing all the keys of an event map that have an acknowledgement callback.
+ *
+ * That also have *some* data coming in.
+ */
+export type EventNamesWithAck<
+  Map extends EventsMap,
+  K extends EventNames<Map> = EventNames<Map>
+> = IfAny<
+  Last<Parameters<Map[K]>> | Map[K],
+  K,
+  K extends (
+    Last<Parameters<Map[K]>> extends (...args: any[]) => any
+      ? FirstNonErrorArg<Last<Parameters<Map[K]>>> extends void
+        ? never
+        : K
+      : never
+  )
+    ? K
+    : never
+>;
+/**
+ * Returns a union type containing all the keys of an event map that have an acknowledgement callback.
+ *
+ * That also have *some* data coming in.
+ */
+export type EventNamesWithoutAck<
+  Map extends EventsMap,
+  K extends EventNames<Map> = EventNames<Map>
+> = IfAny<
+  Last<Parameters<Map[K]>> | Map[K],
+  K,
+  K extends (Parameters<Map[K]> extends never[] ? K : never)
+    ? K
+    : K extends (
+        Last<Parameters<Map[K]>> extends (...args: any[]) => any ? never : K
+      )
+    ? K
+    : never
+>;
+
+export type RemoveAcknowledgements<E extends EventsMap> = {
+  [K in EventNamesWithoutAck<E>]: E[K];
+};
+
+export type EventNamesWithError<
+  Map extends EventsMap,
+  K extends EventNamesWithAck<Map> = EventNamesWithAck<Map>
+> = IfAny<
+  Last<Parameters<Map[K]>> | Map[K],
+  K,
+  K extends (
+    LooseParameters<Last<Parameters<Map[K]>>>[0] extends Error ? K : never
+  )
+    ? K
+    : never
+>;
+
 /** The tuple type representing the parameters of an event listener */
 export type EventParams<
   Map extends EventsMap,
@@ -178,33 +235,96 @@ export abstract class StrictEventEmitter<
     >[];
   }
 }
+/**
+ * Returns a boolean for whether the given type is `any`.
+ *
+ * @link https://stackoverflow.com/a/49928360/1490091
+ *
+ * Useful in type utilities, such as disallowing `any`s to be passed to a function.
+ *
+ * @author sindresorhus
+ * @link https://github.com/sindresorhus/type-fest
+ */
+type IsAny<T> = 0 extends 1 & T ? true : false;
 
-export type Last<T extends any[]> = T extends [...infer H, infer L] ? L : any;
+/**
+ * An if-else-like type that resolves depending on whether the given type is `any`.
+ *
+ * @see {@link IsAny}
+ *
+ * @author sindresorhus
+ * @link https://github.com/sindresorhus/type-fest
+ */
+type IfAny<T, TypeIfAny = true, TypeIfNotAny = false> = IsAny<T> extends true
+  ? TypeIfAny
+  : TypeIfNotAny;
+
+/**
+ * Extracts the type of the last element of an array.
+ *
+ * Use-case: Defining the return type of functions that extract the last element of an array, for example [`lodash.last`](https://lodash.com/docs/4.17.15#last).
+ *
+ * @author sindresorhus
+ * @link https://github.com/sindresorhus/type-fest
+ */
+export type Last<ValueType extends readonly unknown[]> =
+  ValueType extends readonly [infer ElementType]
+    ? ElementType
+    : ValueType extends readonly [infer _, ...infer Tail]
+    ? Last<Tail>
+    : ValueType extends ReadonlyArray<infer ElementType>
+    ? ElementType
+    : never;
+
+export type FirstNonErrorTuple<T extends unknown[]> = T[0] extends Error
+  ? T[1]
+  : T[0];
 export type AllButLast<T extends any[]> = T extends [...infer H, infer L]
   ? H
   : any[];
-export type FirstArg<T> = T extends (arg: infer Param) => infer Result
-  ? Param
-  : any;
-export type SecondArg<T> = T extends (
-  err: Error,
-  arg: infer Param
-) => infer Result
-  ? Param
-  : any;
+/**
+ * Like `Parameters<T>`, but doesn't require `T` to be a function ahead of time.
+ */
+type LooseParameters<T> = T extends (...args: infer P) => any ? P : never;
 
+export type FirstNonErrorArg<T> = T extends (...args: infer Params) => any
+  ? FirstNonErrorTuple<Params>
+  : any;
 type PrependTimeoutError<T extends any[]> = {
   [K in keyof T]: T[K] extends (...args: infer Params) => infer Result
-    ? (err: Error, ...args: Params) => Result
+    ? Params[0] extends Error
+      ? T[K]
+      : (err: Error, ...args: Params) => Result
     : T[K];
 };
 
+export type MultiplyArray<T extends unknown[]> = {
+  [K in keyof T]: T[K][];
+};
+type InferFirstAndPreserveLabel<T extends any[]> = T extends [any, ...infer R]
+  ? T extends [...infer H, ...R]
+    ? H
+    : never
+  : never;
+
+/**
+ * Utility type to decorate the acknowledgement callbacks multiple values
+ * on the first non error element while removing any elements after
+ */
 type ExpectMultipleResponses<T extends any[]> = {
-  [K in keyof T]: T[K] extends (err: Error, arg: infer Param) => infer Result
-    ? (err: Error, arg: Param[]) => Result
+  [K in keyof T]: T[K] extends (...args: infer Params) => infer Result
+    ? Params extends [Error]
+      ? (err: Error) => Result
+      : Params extends [Error, ...infer Rest]
+      ? (
+          err: Error,
+          ...args: InferFirstAndPreserveLabel<MultiplyArray<Rest>>
+        ) => Result
+      : Params extends []
+      ? () => Result
+      : (...args: InferFirstAndPreserveLabel<MultiplyArray<Params>>) => Result
     : T[K];
 };
-
 /**
  * Utility type to decorate the acknowledgement callbacks with a timeout error.
  *

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "socket.io",
-  "version": "4.7.1",
+  "version": "4.7.3",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "socket.io",
-      "version": "4.7.1",
+      "version": "4.7.3",
       "license": "MIT",
       "dependencies": {
         "accepts": "~1.3.4",
@@ -24,12 +24,12 @@
         "nyc": "^15.1.0",
         "prettier": "^2.3.2",
         "rimraf": "^3.0.2",
-        "socket.io-client": "4.7.2",
+        "socket.io-client": "4.7.4",
         "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
         "superagent": "^8.0.0",
         "supertest": "^6.1.6",
         "ts-node": "^10.2.1",
-        "tsd": "^0.21.0",
+        "tsd": "^0.27.0",
         "typescript": "^4.4.2",
         "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.30.0"
       },
@@ -646,14 +646,10 @@
       "dev": true
     },
     "node_modules/@tsd/typescript": {
-      "version": "4.7.4",
-      "resolved": "https://registry.npmjs.org/@tsd/typescript/-/typescript-4.7.4.tgz",
-      "integrity": "sha512-jbtC+RgKZ9Kk65zuRZbKLTACf+tvFW4Rfq0JEMXrlmV3P3yme+Hm+pnb5fJRyt61SjIitcrC810wj7+1tgsEmg==",
-      "dev": true,
-      "bin": {
-        "tsc": "typescript/bin/tsc",
-        "tsserver": "typescript/bin/tsserver"
-      }
+      "version": "4.9.5",
+      "resolved": "https://registry.npmjs.org/@tsd/typescript/-/typescript-4.9.5.tgz",
+      "integrity": "sha512-+UgxOvJUl5rQdPFSSOOwhmSmpThm8DJ3HwHxAOq5XYe7CcmG1LcM2QeqWwILzUIT5tbeMqY8qABiCsRtIjk/2g==",
+      "dev": true
     },
     "node_modules/@types/cookie": {
       "version": "0.4.1",
@@ -1877,6 +1873,15 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/hasha/node_modules/type-fest": {
+      "version": "0.8.1",
+      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+      "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+      "dev": true,
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/he": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/he/-/he-1.2.0.tgz",
@@ -3199,6 +3204,15 @@
         "node": ">=8"
       }
     },
+    "node_modules/read-pkg-up/node_modules/type-fest": {
+      "version": "0.8.1",
+      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+      "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+      "dev": true,
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/read-pkg/node_modules/hosted-git-info": {
       "version": "2.8.9",
       "resolved": "https://registry.npmjs.org/hosted-git-info/-/hosted-git-info-2.8.9.tgz",
@@ -3464,9 +3478,9 @@
       }
     },
     "node_modules/socket.io-client": {
-      "version": "4.7.2",
-      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.7.2.tgz",
-      "integrity": "sha512-vtA0uD4ibrYD793SOIAwlo8cj6haOeMHrGvwPxJsxH7CeIksqJ+3Zc06RvWTIFgiSqx4A3sOnTXpfAEE2Zyz6w==",
+      "version": "4.7.4",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.7.4.tgz",
+      "integrity": "sha512-wh+OkeF0rAVCrABWQBaEjLfb7DVPotMbu0cgWgyR0v6eA4EoVnAwcIeIbcdTE3GT/H3kbdLl7OoH2+asoDRIIg==",
       "dev": true,
       "dependencies": {
         "@socket.io/component-emitter": "~3.1.0",
@@ -4014,12 +4028,12 @@
       }
     },
     "node_modules/tsd": {
-      "version": "0.21.0",
-      "resolved": "https://registry.npmjs.org/tsd/-/tsd-0.21.0.tgz",
-      "integrity": "sha512-6DugCw1Q4H8HYwDT3itzgALjeDxN4RO3iqu7gRdC/YNVSCRSGXRGQRRasftL1uKDuKxlFffYKHv5j5G7YnKGxQ==",
+      "version": "0.27.0",
+      "resolved": "https://registry.npmjs.org/tsd/-/tsd-0.27.0.tgz",
+      "integrity": "sha512-G/2Sejk9N21TcuWlHwrvVWwIyIl2mpECFPbnJvFMsFN1xQCIbi2QnvG4fkw3VitFhNF6dy38cXxKJ8Paq8kOGQ==",
       "dev": true,
       "dependencies": {
-        "@tsd/typescript": "~4.7.3",
+        "@tsd/typescript": "~4.9.5",
         "eslint-formatter-pretty": "^4.1.0",
         "globby": "^11.0.1",
         "meow": "^9.0.0",
@@ -4030,16 +4044,7 @@
         "tsd": "dist/cli.js"
       },
       "engines": {
-        "node": ">=12"
-      }
-    },
-    "node_modules/type-fest": {
-      "version": "0.8.1",
-      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
-      "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
-      "dev": true,
-      "engines": {
-        "node": ">=8"
+        "node": ">=14.16"
       }
     },
     "node_modules/typedarray-to-buffer": {
@@ -4825,9 +4830,9 @@
       "dev": true
     },
     "@tsd/typescript": {
-      "version": "4.7.4",
-      "resolved": "https://registry.npmjs.org/@tsd/typescript/-/typescript-4.7.4.tgz",
-      "integrity": "sha512-jbtC+RgKZ9Kk65zuRZbKLTACf+tvFW4Rfq0JEMXrlmV3P3yme+Hm+pnb5fJRyt61SjIitcrC810wj7+1tgsEmg==",
+      "version": "4.9.5",
+      "resolved": "https://registry.npmjs.org/@tsd/typescript/-/typescript-4.9.5.tgz",
+      "integrity": "sha512-+UgxOvJUl5rQdPFSSOOwhmSmpThm8DJ3HwHxAOq5XYe7CcmG1LcM2QeqWwILzUIT5tbeMqY8qABiCsRtIjk/2g==",
       "dev": true
     },
     "@types/cookie": {
@@ -5754,6 +5759,14 @@
       "requires": {
         "is-stream": "^2.0.0",
         "type-fest": "^0.8.0"
+      },
+      "dependencies": {
+        "type-fest": {
+          "version": "0.8.1",
+          "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+          "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+          "dev": true
+        }
       }
     },
     "he": {
@@ -6754,6 +6767,12 @@
           "requires": {
             "p-limit": "^2.2.0"
           }
+        },
+        "type-fest": {
+          "version": "0.8.1",
+          "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+          "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+          "dev": true
         }
       }
     },
@@ -6923,9 +6942,9 @@
       }
     },
     "socket.io-client": {
-      "version": "4.7.2",
-      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.7.2.tgz",
-      "integrity": "sha512-vtA0uD4ibrYD793SOIAwlo8cj6haOeMHrGvwPxJsxH7CeIksqJ+3Zc06RvWTIFgiSqx4A3sOnTXpfAEE2Zyz6w==",
+      "version": "4.7.4",
+      "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.7.4.tgz",
+      "integrity": "sha512-wh+OkeF0rAVCrABWQBaEjLfb7DVPotMbu0cgWgyR0v6eA4EoVnAwcIeIbcdTE3GT/H3kbdLl7OoH2+asoDRIIg==",
       "dev": true,
       "requires": {
         "@socket.io/component-emitter": "~3.1.0",
@@ -7346,12 +7365,12 @@
       }
     },
     "tsd": {
-      "version": "0.21.0",
-      "resolved": "https://registry.npmjs.org/tsd/-/tsd-0.21.0.tgz",
-      "integrity": "sha512-6DugCw1Q4H8HYwDT3itzgALjeDxN4RO3iqu7gRdC/YNVSCRSGXRGQRRasftL1uKDuKxlFffYKHv5j5G7YnKGxQ==",
+      "version": "0.27.0",
+      "resolved": "https://registry.npmjs.org/tsd/-/tsd-0.27.0.tgz",
+      "integrity": "sha512-G/2Sejk9N21TcuWlHwrvVWwIyIl2mpECFPbnJvFMsFN1xQCIbi2QnvG4fkw3VitFhNF6dy38cXxKJ8Paq8kOGQ==",
       "dev": true,
       "requires": {
-        "@tsd/typescript": "~4.7.3",
+        "@tsd/typescript": "~4.9.5",
         "eslint-formatter-pretty": "^4.1.0",
         "globby": "^11.0.1",
         "meow": "^9.0.0",
@@ -7359,12 +7378,6 @@
         "read-pkg-up": "^7.0.0"
       }
     },
-    "type-fest": {
-      "version": "0.8.1",
-      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
-      "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
-      "dev": true
-    },
     "typedarray-to-buffer": {
       "version": "3.1.5",
       "resolved": "https://registry.npmjs.org/typedarray-to-buffer/-/typedarray-to-buffer-3.1.5.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "socket.io",
-  "version": "4.7.2",
+  "version": "4.7.4",
   "description": "node.js realtime framework server",
   "keywords": [
     "realtime",
@@ -61,12 +61,12 @@
     "nyc": "^15.1.0",
     "prettier": "^2.3.2",
     "rimraf": "^3.0.2",
-    "socket.io-client": "4.7.2",
+    "socket.io-client": "4.7.4",
     "socket.io-client-v2": "npm:socket.io-client@^2.4.0",
     "superagent": "^8.0.0",
     "supertest": "^6.1.6",
     "ts-node": "^10.2.1",
-    "tsd": "^0.21.0",
+    "tsd": "^0.27.0",
     "typescript": "^4.4.2",
     "uWebSockets.js": "github:uNetworking/uWebSockets.js#v20.30.0"
   },

test/connection-state-recovery.ts

@@ -222,11 +222,11 @@ describe("connection state recovery", () => {
 
     class DummyAdapter extends Adapter {
       override persistSession(session) {
-        expect.fail();
+        expect().fail();
       }
 
       override restoreSession(pid, offset) {
-        expect.fail();
+        expect().fail();
         return Promise.reject("should not happen");
       }
     }

test/messaging-many.ts

@@ -526,7 +526,7 @@ describe("messaging many", () => {
     ]).then(async () => {
       try {
         await io.timeout(200).emitWithAck("some event");
-        expect.fail();
+        expect().fail();
       } catch (err) {
         expect(err).to.be.an(Error);
         // @ts-ignore

test/namespaces.ts

@@ -6,6 +6,7 @@ import {
   createClient,
   successFn,
   createPartialDone,
+  assert,
 } from "./support/util";
 
 describe("namespaces", () => {
@@ -62,7 +63,7 @@ describe("namespaces", () => {
     const io = new Server(0);
     const clientSocket = createClient(io);
 
-    io.on("connect", (socket) => {
+    io.on("connection", (socket) => {
       expect(socket).to.be.a(Socket);
       success(done, io, clientSocket);
     });
@@ -417,6 +418,7 @@ describe("namespaces", () => {
     socket1.on("a", successFn(done, io, socket1, socket2));
 
     socket2.on("connect", () => {
+      assert(socket2.id);
       io.except(socket2.id).emit("a");
     });
   });
@@ -435,6 +437,7 @@ describe("namespaces", () => {
     socket1.on("a", successFn(done, io, socket1, socket2));
 
     socket2.on("connect", () => {
+      assert(socket2.id);
       nsp.except(socket2.id).emit("a");
     });
   });

test/socket-timeout.ts

@@ -62,7 +62,7 @@ describe("timeout", () => {
     io.on("connection", async (socket) => {
       try {
         await socket.timeout(50).emitWithAck("unknown");
-        expect.fail();
+        expect().fail();
       } catch (err) {
         expect(err).to.be.an(Error);
         success(done, io, client);

test/socket.io.test-d.ts

@@ -1,10 +1,14 @@
 "use strict";
-import { Namespace, Server, Socket } from "..";
-import type { DefaultEventsMap } from "../lib/typed-events";
 import { createServer } from "http";
-import { expectError, expectType } from "tsd";
 import { Adapter } from "socket.io-adapter";
-import type { DisconnectReason } from "../lib/socket";
+import { expectType } from "tsd";
+import {
+  BroadcastOperator,
+  Server,
+  Socket,
+  type DisconnectReason,
+} from "../lib/index";
+import type { DefaultEventsMap, EventsMap } from "../lib/typed-events";
 
 // This file is run by tsd, not mocha.
 
@@ -24,7 +28,7 @@ describe("server", () => {
               expectType<DisconnectReason>(reason);
             });
           });
-          sio.on("connect", (s) => {
+          sio.on("connection", (s) => {
             expectType<Socket<DefaultEventsMap, DefaultEventsMap>>(s);
           });
           done();
@@ -61,8 +65,7 @@ describe("server", () => {
           }
 
           sio.on(Events.CONNECTION, (socket) => {
-            // TODO(#3833): Make this expect `Socket<DefaultEventsMap, DefaultEventsMap>`
-            expectType<any>(socket);
+            expectType<Socket<DefaultEventsMap, DefaultEventsMap>>(socket);
 
             socket.on("test", (a, b, c) => {
               expectType<any>(a);
@@ -85,6 +88,8 @@ describe("server", () => {
         const srv = createServer();
         const sio = new Server(srv);
         srv.listen(() => {
+          sio.emit("random", 1, "2", [3]);
+          sio.emit("no parameters");
           sio.on("connection", (s) => {
             s.emit("random", 1, "2", [3]);
             s.emit("no parameters");
@@ -92,6 +97,17 @@ describe("server", () => {
         });
       });
     });
+    describe("send", () => {
+      it("accepts any parameters", () => {
+        const srv = createServer();
+        const sio = new Server(srv);
+        const nio = sio.of("/test");
+        sio.send(1, "2", [3]);
+        sio.send();
+        nio.send(1, "2", [3]);
+        nio.send();
+      });
+    });
 
     describe("emitWithAck", () => {
       it("accepts any parameters", () => {
@@ -144,79 +160,363 @@ describe("server", () => {
         const sio = new Server<BidirectionalEvents, BidirectionalEvents, {}>(
           srv
         );
-        expectError(sio.on("random", (a, b, c) => {}));
+        // @ts-expect-error - shouldn't accept arguments of the wrong types
+        sio.on("random", (a, b, c) => {});
         srv.listen(() => {
-          expectError(sio.on("wrong name", (s) => {}));
+          // @ts-expect-error - shouldn't accept arguments of the wrong types
+          sio.on("wrong name", (s) => {});
           sio.on("connection", (s) => {
             s.on("random", (a, b, c) => {});
-            expectError(s.on("random"));
-            expectError(s.on("random", (a, b, c, d) => {}));
-            expectError(s.on(2, 3));
-          });
-        });
-      });
-    });
-
-    describe("emit", () => {
-      it("accepts arguments of the correct types", () => {
-        const srv = createServer();
-        const sio = new Server<BidirectionalEvents>(srv);
-        srv.listen(() => {
-          sio.on("connection", (s) => {
-            s.emit("random", 1, "2", [3]);
-          });
-        });
-      });
-
-      it("does not accept arguments of the wrong types", () => {
-        const srv = createServer();
-        const sio = new Server<BidirectionalEvents>(srv);
-        srv.listen(() => {
-          sio.on("connection", (s) => {
-            expectError(s.emit("noParameter", 2));
-            expectError(s.emit("oneParameter"));
-            expectError(s.emit("random"));
-            expectError(s.emit("oneParameter", 2, 3));
-            expectError(s.emit("random", (a, b, c) => {}));
-            expectError(s.emit("wrong name", () => {}));
-            expectError(s.emit("complicated name with spaces", 2));
+            // @ts-expect-error - shouldn't accept arguments of the wrong types
+            s.on("random");
+            // @ts-expect-error - shouldn't accept arguments of the wrong types
+            s.on("random", (a, b, c, d) => {});
+            // @ts-expect-error - shouldn't accept arguments of the wrong types
+            s.on(2, 3);
           });
         });
       });
     });
   });
+  type ToEmit<Map extends EventsMap, Ev extends keyof Map = keyof Map> = (
+    ev: Ev,
+    ...args: Parameters<Map[Ev]>
+  ) => boolean;
+  type ToEmitWithAck<
+    Map extends EventsMap,
+    Ev extends keyof Map = keyof Map
+  > = (ev: Ev, ...args: Parameters<Map[Ev]>) => ReturnType<Map[Ev]>;
+  interface ClientToServerEvents {
+    noArgs: () => void;
+    helloFromClient: (message: string) => void;
+    ackFromClient: (
+      a: string,
+      b: number,
+      ack: (c: string, d: number) => void
+    ) => void;
+  }
 
+  interface ServerToClientEvents {
+    noArgs: () => void;
+    helloFromServer: (message: string, x: number) => void;
+    ackFromServer: (
+      a: boolean,
+      b: string,
+      ack: (c: boolean, d: string) => void
+    ) => void;
+    ackFromServerSingleArg: (
+      a: boolean,
+      b: string,
+      ack: (c: string) => void
+    ) => void;
+    onlyCallback: (a: () => void) => void;
+  }
+  // While these could be generated using the types from typed-events,
+  // it's likely better to just write them out, so that both the types and this are tested properly
+  interface ServerToClientEventsNoAck {
+    noArgs: () => void;
+    helloFromServer: (message: string, x: number) => void;
+    ackFromServer: never;
+    ackFromServerSingleArg: never;
+    onlyCallback: never;
+  }
+  interface ServerToClientEventsWithError {
+    noArgs: () => void;
+    helloFromServer: (message: string, x: number) => void;
+    ackFromServer: (
+      a: boolean,
+      b: string,
+      ack: (err: Error, c: boolean, d: string) => void
+    ) => void;
+    ackFromServerSingleArg: (
+      a: boolean,
+      b: string,
+      ack: (err: Error, c: string) => void
+    ) => void;
+    onlyCallback: (a: (err: Error) => void) => void;
+  }
+
+  interface ServerToClientEventsWithMultiple {
+    noArgs: () => void;
+    helloFromServer: (message: string, x: number) => void;
+    ackFromServer: (a: boolean, b: string, ack: (c: boolean[]) => void) => void;
+    ackFromServerSingleArg: (
+      a: boolean,
+      b: string,
+      ack: (c: string[]) => void
+    ) => void;
+    onlyCallback: (a: () => void) => void;
+  }
+  interface ServerToClientEventsWithMultipleAndError {
+    noArgs: () => void;
+    helloFromServer: (message: string, x: number) => void;
+    ackFromServer: (
+      a: boolean,
+      b: string,
+      ack: (err: Error, c: boolean[]) => void
+    ) => void;
+    ackFromServerSingleArg: (
+      a: boolean,
+      b: string,
+      ack: (err: Error, c: string[]) => void
+    ) => void;
+    onlyCallback: (a: (err: Error) => void) => void;
+  }
+  interface ServerToClientEventsWithMultipleWithAck {
+    ackFromServer: (a: boolean, b: string) => Promise<boolean[]>;
+    ackFromServerSingleArg: (a: boolean, b: string) => Promise<string[]>;
+    // This should technically be `undefined[]`, but this doesn't work currently *only* with emitWithAck
+    // you can use an empty callback with emit, but not emitWithAck
+    onlyCallback: () => Promise<undefined>;
+  }
+  interface ServerToClientEventsWithAck {
+    ackFromServer: (a: boolean, b: string) => Promise<boolean>;
+    ackFromServerSingleArg: (a: boolean, b: string) => Promise<string>;
+    // This doesn't work currently *only* with emitWithAck
+    // you can use an empty callback with emit, but not emitWithAck
+    onlyCallback: () => Promise<undefined>;
+  }
+  describe("Emitting Types", () => {
+    describe("send", () => {
+      it("prevents arguments if EmitEvents doesn't have message", () => {
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        const nio = sio.of("/test");
+        // @ts-expect-error - ServerToClientEvents doesn't have a message event
+        sio.send(1, "2", [3]);
+        // @ts-expect-error - ServerToClientEvents doesn't have a message event
+        nio.send(1, "2", [3]);
+        // This correctly becomes an error in TS 5.3.2, so when updating typescript, this should expect-error
+        sio.send();
+        nio.send();
+      });
+      it("has the correct types", () => {
+        const sio = new Server<
+          {},
+          { message: (a: number, b: string, c: number[]) => void }
+        >();
+        const nio = sio.of("/test");
+        sio.send(1, "2", [3]);
+        nio.send(1, "2", [3]);
+        // @ts-expect-error - message requires arguments
+        sio.send();
+        // @ts-expect-error - message requires arguments
+        nio.send();
+        // @ts-expect-error - message requires the correct arguments
+        sio.send(1, 2, [3]);
+        // @ts-expect-error - message requires the correct arguments
+        nio.send(1, 2, [3]);
+      });
+    });
+    describe("Broadcast Operator", () => {
+      it("works untyped", () => {
+        const untyped = new Server();
+        untyped.emit("random", 1, 2, Function, Boolean);
+        untyped.of("/").emit("random2", 2, "string", Server);
+        expectType<Promise<any>>(untyped.to("1").emitWithAck("random", "test"));
+        expectType<(ev: string, ...args: any[]) => Promise<any>>(
+          untyped.to("1").emitWithAck<string>
+        );
+      });
+      it("has the correct types", () => {
+        // Ensuring that all paths to BroadcastOperator have the correct types
+        // means that we only need one set of tests for emitting once the
+        // socket/namespace/server becomes a broadcast emitter
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        const nio = sio.of("/");
+        for (const emitter of [sio, nio]) {
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.to("1")
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.in("1")
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.except("1")
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.except("1")
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.compress(true)
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.volatile
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            emitter.local
+          );
+          expectType<
+            BroadcastOperator<ServerToClientEventsWithMultipleAndError, any>
+          >(emitter.timeout(0));
+          expectType<
+            BroadcastOperator<ServerToClientEventsWithMultipleAndError, any>
+          >(emitter.timeout(0).timeout(0));
+        }
+        sio.on("connection", (s) => {
+          expectType<
+            Socket<
+              ClientToServerEvents,
+              ServerToClientEventsWithError,
+              DefaultEventsMap,
+              any
+            >
+          >(s.timeout(0));
+          expectType<
+            BroadcastOperator<ServerToClientEventsWithMultipleAndError, any>
+          >(s.timeout(0).broadcast);
+          // ensure that turning socket to a broadcast works correctly
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            s.broadcast
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            s.in("1")
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            s.except("1")
+          );
+          expectType<BroadcastOperator<ServerToClientEventsWithMultiple, any>>(
+            s.to("1")
+          );
+          // Ensure that adding a timeout to a broadcast works after the fact
+          expectType<
+            BroadcastOperator<ServerToClientEventsWithMultipleAndError, any>
+          >(s.broadcast.timeout(0));
+          // Ensure that adding a timeout to a broadcast works after the fact
+          expectType<
+            BroadcastOperator<ServerToClientEventsWithMultipleAndError, any>
+          >(s.broadcast.timeout(0).timeout(0));
+        });
+      });
+      it("has the correct types for `emit`", () => {
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        expectType<ToEmit<ServerToClientEventsWithMultipleAndError, "noArgs">>(
+          sio.timeout(0).emit<"noArgs">
+        );
+        expectType<
+          ToEmit<ServerToClientEventsWithMultipleAndError, "helloFromServer">
+        >(sio.timeout(0).emit<"helloFromServer">);
+        expectType<
+          ToEmit<
+            ServerToClientEventsWithMultipleAndError,
+            "ackFromServerSingleArg"
+          >
+        >(sio.timeout(0).emit<"ackFromServerSingleArg">);
+        expectType<
+          ToEmit<ServerToClientEventsWithMultipleAndError, "ackFromServer">
+        >(sio.timeout(0).emit<"ackFromServer">);
+        expectType<
+          ToEmit<ServerToClientEventsWithMultipleAndError, "onlyCallback">
+        >(sio.timeout(0).emit<"onlyCallback">);
+      });
+      it("has the correct types for `emitWithAck`", () => {
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        const sansTimeout = sio.in("1");
+        // Without timeout, `emitWithAck` shouldn't accept any events
+        expectType<never>(
+          undefined as Parameters<typeof sansTimeout["emitWithAck"]>[0]
+        );
+        // @ts-expect-error - "noArgs" doesn't have a callback and is thus excluded
+        sio.timeout(0).emitWithAck("noArgs");
+        // @ts-expect-error - "helloFromServer" doesn't have a callback and is thus excluded
+        sio.timeout(0).emitWithAck("helloFromServer");
+        // @ts-expect-error - "onlyCallback" doesn't have a callback and is thus excluded
+        sio.timeout(0).emitWithAck("onlyCallback");
+        expectType<
+          ToEmitWithAck<
+            ServerToClientEventsWithMultipleWithAck,
+            "ackFromServerSingleArg"
+          >
+        >(sio.timeout(0).emitWithAck<"ackFromServerSingleArg">);
+        expectType<
+          ToEmitWithAck<
+            ServerToClientEventsWithMultipleWithAck,
+            "ackFromServer"
+          >
+        >(sio.timeout(0).emitWithAck<"ackFromServer">);
+      });
+    });
+    describe("emit", () => {
+      it("Infers correct types", () => {
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        const nio = sio.of("/test");
+        expectType<ToEmit<ServerToClientEventsNoAck, "noArgs">>(
+          sio.emit<"noArgs">
+        );
+        expectType<ToEmit<ServerToClientEventsNoAck, "noArgs">>(
+          nio.emit<"noArgs">
+        );
+        expectType<ToEmit<ServerToClientEventsNoAck, "helloFromServer">>(
+          // These errors will dissapear once the TS version is updated from 4.7.4
+          // the TSD instance is using a newer version of TS than the workspace version
+          // to enable the ability to compare against `any`
+          sio.emit<"helloFromServer">
+        );
+        expectType<ToEmit<ServerToClientEventsNoAck, "helloFromServer">>(
+          nio.emit<"helloFromServer">
+        );
+        sio.on("connection", (s) => {
+          expectType<ToEmit<ServerToClientEvents, "noArgs">>(s.emit<"noArgs">);
+          expectType<ToEmit<ServerToClientEvents, "helloFromServer">>(
+            s.emit<"helloFromServer">
+          );
+          expectType<ToEmit<ServerToClientEvents, "ackFromServerSingleArg">>(
+            s.emit<"ackFromServerSingleArg">
+          );
+          expectType<ToEmit<ServerToClientEvents, "ackFromServer">>(
+            s.emit<"ackFromServer">
+          );
+          expectType<ToEmit<ServerToClientEvents, "onlyCallback">>(
+            s.emit<"onlyCallback">
+          );
+        });
+      });
+      it("does not allow events with acks", () => {
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        const nio = sio.of("/test");
+        // @ts-expect-error - "ackFromServerSingleArg" has a callback and is thus excluded
+        sio.emit<"ackFromServerSingleArg">;
+        // @ts-expect-error - "ackFromServer" has a callback and is thus excluded
+        sio.emit<"ackFromServer">;
+        // @ts-expect-error - "onlyCallback" has a callback and is thus excluded
+        sio.emit<"onlyCallback">;
+        // @ts-expect-error - "ackFromServerSingleArg" has a callback and is thus excluded
+        nio.emit<"ackFromServerSingleArg">;
+        // @ts-expect-error - "ackFromServer" has a callback and is thus excluded
+        nio.emit<"ackFromServer">;
+        // @ts-expect-error - "onlyCallback" has a callback and is thus excluded
+        nio.emit<"onlyCallback">;
+      });
+    });
+    describe("emitWithAck", () => {
+      it("Infers correct types", () => {
+        const sio = new Server<ClientToServerEvents, ServerToClientEvents>();
+        sio.on("connection", (s) => {
+          // @ts-expect-error - "noArgs" doesn't have a callback and is thus excluded
+          s.emitWithAck("noArgs");
+          // @ts-expect-error - "helloFromServer" doesn't have a callback and is thus excluded
+          s.emitWithAck("helloFromServer");
+          // @ts-expect-error - "onlyCallback" doesn't have a callback and is thus excluded
+          s.emitWithAck("onlyCallback");
+          // @ts-expect-error - "onlyCallback" doesn't have a callback and is thus excluded
+          s.timeout(0).emitWithAck("onlyCallback");
+          expectType<
+            ToEmitWithAck<ServerToClientEventsWithAck, "ackFromServerSingleArg">
+          >(s.emitWithAck<"ackFromServerSingleArg">);
+          expectType<
+            ToEmitWithAck<ServerToClientEventsWithAck, "ackFromServer">
+          >(s.emitWithAck<"ackFromServer">);
+
+          expectType<
+            ToEmitWithAck<ServerToClientEventsWithAck, "ackFromServerSingleArg">
+          >(s.timeout(0).emitWithAck<"ackFromServerSingleArg">);
+          expectType<
+            ToEmitWithAck<ServerToClientEventsWithAck, "ackFromServer">
+          >(s.timeout(0).emitWithAck<"ackFromServer">);
+        });
+      });
+    });
+  });
   describe("listen and emit event maps", () => {
-    interface ClientToServerEvents {
-      helloFromClient: (message: string) => void;
-      ackFromClient: (
-        a: string,
-        b: number,
-        ack: (c: string, d: number) => void
-      ) => void;
-    }
-
-    interface ServerToClientEvents {
-      helloFromServer: (message: string, x: number) => void;
-      ackFromServer: (
-        a: boolean,
-        b: string,
-        ack: (c: boolean, d: string) => void
-      ) => void;
-
-      ackFromServerSingleArg: (
-        a: boolean,
-        b: string,
-        ack: (c: string) => void
-      ) => void;
-
-      multipleAckFromServer: (
-        a: boolean,
-        b: string,
-        ack: (c: string) => void
-      ) => void;
-    }
-
     describe("on", () => {
       it("infers correct types for listener parameters", (done) => {
         const srv = createServer();
@@ -225,6 +525,10 @@ describe("server", () => {
         srv.listen(() => {
           sio.on("connection", (s) => {
             expectType<Socket<ClientToServerEvents, ServerToClientEvents>>(s);
+            s.on("noArgs", (...args) => {
+              expectType<[]>(args);
+              done();
+            });
             s.on("helloFromClient", (message) => {
               expectType<string>(message);
               done();
@@ -245,117 +549,14 @@ describe("server", () => {
         const sio = new Server<ClientToServerEvents, ServerToClientEvents>(srv);
         srv.listen(() => {
           sio.on("connection", (s) => {
-            expectError(
-              s.on("helloFromServer", (message, number) => {
-                done();
-              })
-            );
-          });
-        });
-      });
-    });
-
-    describe("emit", () => {
-      it("accepts arguments of the correct types", (done) => {
-        const srv = createServer();
-        const sio = new Server<ClientToServerEvents, ServerToClientEvents>(srv);
-        srv.listen(() => {
-          sio.emit("helloFromServer", "hi", 1);
-          sio.to("room").emit("helloFromServer", "hi", 1);
-          sio.timeout(1000).emit("helloFromServer", "hi", 1);
-
-          sio
-            .timeout(1000)
-            .emit("multipleAckFromServer", true, "123", (err, c) => {
-              expectType<Error>(err);
-              expectType<string[]>(c);
+            // @ts-expect-error - shouldn't accept emit events
+            s.on("noArgs", (message, number) => {
+              done();
             });
-
-          sio.on("connection", (s) => {
-            s.emit("helloFromServer", "hi", 10);
-
-            s.emit("ackFromServer", true, "123", (c, d) => {
-              expectType<boolean>(c);
-              expectType<string>(d);
+            // @ts-expect-error - shouldn't accept emit events
+            s.on("helloFromServer", (message, number) => {
+              done();
             });
-
-            s.timeout(1000).emit("ackFromServer", true, "123", (err, c, d) => {
-              expectType<Error>(err);
-              expectType<boolean>(c);
-              expectType<string>(d);
-            });
-
-            s.timeout(1000)
-              .to("room")
-              .emit("multipleAckFromServer", true, "123", (err, c) => {
-                expectType<Error>(err);
-                expectType<string[]>(c);
-              });
-
-            s.to("room")
-              .timeout(1000)
-              .emit("multipleAckFromServer", true, "123", (err, c) => {
-                expectType<Error>(err);
-                expectType<string[]>(c);
-              });
-
-            done();
-          });
-        });
-      });
-
-      it("does not accept arguments of wrong types", (done) => {
-        const srv = createServer();
-        const sio = new Server<ClientToServerEvents, ServerToClientEvents>(srv);
-        srv.listen(() => {
-          expectError(sio.emit("helloFromClient"));
-          expectError(sio.to("room").emit("helloFromClient"));
-          expectError(sio.timeout(1000).to("room").emit("helloFromClient"));
-
-          sio.on("connection", (s) => {
-            expectError(s.emit("helloFromClient", "hi"));
-            expectError(s.emit("helloFromServer", "hi", 10, "10"));
-            expectError(s.emit("helloFromServer", "hi", "10"));
-            expectError(s.emit("helloFromServer", 0, 0));
-            expectError(s.emit("wrong name", 10));
-            expectError(s.emit("wrong name"));
-            done();
-          });
-        });
-      });
-    });
-
-    describe("emitWithAck", () => {
-      it("accepts arguments of the correct types", (done) => {
-        const srv = createServer();
-        const sio = new Server<ClientToServerEvents, ServerToClientEvents>(srv);
-        srv.listen(async () => {
-          const value = await sio
-            .timeout(1000)
-            .emitWithAck("multipleAckFromServer", true, "123");
-          expectType<string[]>(value);
-
-          sio.on("connection", async (s) => {
-            const value1 = await s
-              .timeout(1000)
-              .to("room")
-              .emitWithAck("multipleAckFromServer", true, "123");
-            expectType<string[]>(value1);
-
-            const value2 = await s
-              .to("room")
-              .timeout(1000)
-              .emitWithAck("multipleAckFromServer", true, "123");
-            expectType<string[]>(value2);
-
-            const value3 = await s.emitWithAck(
-              "ackFromServerSingleArg",
-              true,
-              "123"
-            );
-            expectType<string>(value3);
-
-            done();
           });
         });
       });
@@ -364,14 +565,17 @@ describe("server", () => {
 
   describe("listen and emit event maps for the serverSideEmit method", () => {
     interface ClientToServerEvents {
+      noArgs: () => void;
       helloFromClient: (message: string) => void;
     }
 
     interface ServerToClientEvents {
+      noArgs: () => void;
       helloFromServer: (message: string, x: number) => void;
     }
 
     interface InterServerEvents {
+      noArgs: () => void;
       helloFromServerToServer: (message: string, x: number) => void;
       ackFromServerToServer: (foo: string, cb: (bar: number) => void) => void;
     }
@@ -389,20 +593,36 @@ describe("server", () => {
           Server<ClientToServerEvents, ServerToClientEvents, InterServerEvents>
         >(sio);
         srv.listen(async () => {
+          sio.serverSideEmit("noArgs");
           sio.serverSideEmit("helloFromServerToServer", "hello", 10);
           sio
             .of("/test")
             .serverSideEmit("helloFromServerToServer", "hello", 10);
 
+          sio.on("noArgs", (...args) => {
+            expectType<[]>(args);
+          });
           sio.on("helloFromServerToServer", (message, x) => {
             expectType<string>(message);
             expectType<number>(x);
           });
+          sio.of("/test").on("noArgs", (...args) => {
+            expectType<[]>(args);
+          });
           sio.of("/test").on("helloFromServerToServer", (message, x) => {
             expectType<string>(message);
             expectType<number>(x);
           });
 
+          //@ts-expect-error - "helloFromServerToServer" does not have a callback
+          sio.serverSideEmitWithAck("noArgs");
+          //@ts-expect-error - "helloFromServerToServer" does not have a callback
+          sio.serverSideEmitWithAck("helloFromServerToServer", "hello");
+
+          sio.on("ackFromServerToServer", (...args) => {
+            expectType<[string, (bar: number) => void]>(args);
+          });
+
           sio.serverSideEmit("ackFromServerToServer", "foo", (err, bar) => {
             expectType<Error>(err);
             expectType<number[]>(bar);
@@ -440,7 +660,8 @@ describe("server", () => {
 
     it("does not accept arguments of wrong types", () => {
       const io = new Server();
-      expectError(io.adapter((nsp) => "nope"));
+      // @ts-expect-error - shouldn't accept arguments of the wrong types
+      io.adapter((nsp) => "nope");
     });
   });
 });

test/socket.ts

@@ -606,9 +606,11 @@ describe("socket", () => {
   });
 
   it("should emit an event and wait for the acknowledgement", (done) => {
-    const io = new Server(0);
-    const socket = createClient(io);
-
+    type Events = {
+      hi: (a: number, b: number, cb: (c: number) => void) => void;
+    };
+    const io = new Server<{}, Events>(0);
+    const socket = createClient<Events, Events>(io);
     io.on("connection", async (s) => {
       socket.on("hi", (a, b, fn) => {
         expect(a).to.be(1);

test/support/expectjs.d.ts

@@ -0,0 +1,221 @@
+declare function expect(target?: any): Expect.Root;
+
+declare namespace Expect {
+  interface Assertion {
+    /**
+     * Check if the value is truthy
+     */
+    ok(): void;
+
+    /**
+     * Creates an anonymous function which calls fn with arguments.
+     */
+    withArgs(...args: any[]): Root;
+
+    /**
+     * Assert that the function throws.
+     *
+     * @param fn callback to match error string against
+     */
+    throwError(fn?: (exception: any) => void): void;
+
+    /**
+     * Assert that the function throws.
+     *
+     * @param fn callback to match error string against
+     */
+    throwException(fn?: (exception: any) => void): void;
+
+    /**
+     * Assert that the function throws.
+     *
+     * @param regexp regexp to match error string against
+     */
+    throwError(regexp: RegExp): void;
+
+    /**
+     * Assert that the function throws.
+     *
+     * @param fn callback to match error string against
+     */
+    throwException(regexp: RegExp): void;
+
+    /**
+     * Checks if the array is empty.
+     */
+    empty(): Assertion;
+
+    /**
+     * Checks if the obj exactly equals another.
+     */
+    equal(obj: any): Assertion;
+
+    /**
+     * Checks if the obj sortof equals another.
+     */
+    eql(obj: any): Assertion;
+
+    /**
+     * Assert within start to finish (inclusive).
+     *
+     * @param start
+     * @param finish
+     */
+    within(start: number, finish: number): Assertion;
+
+    /**
+     * Assert typeof.
+     */
+    a(type: string): Assertion;
+
+    /**
+     * Assert instanceof.
+     */
+    a(type: Function): Assertion;
+
+    /**
+     * Assert typeof / instanceof.
+     */
+    an: An;
+
+    /**
+     * Assert numeric value above n.
+     */
+    greaterThan(n: number): Assertion;
+
+    /**
+     * Assert numeric value above n.
+     */
+    above(n: number): Assertion;
+
+    /**
+     * Assert numeric value below n.
+     */
+    lessThan(n: number): Assertion;
+
+    /**
+     * Assert numeric value below n.
+     */
+    below(n: number): Assertion;
+
+    /**
+     * Assert string value matches regexp.
+     *
+     * @param regexp
+     */
+    match(regexp: RegExp): Assertion;
+
+    /**
+     * Assert property "length" exists and has value of n.
+     *
+     * @param n
+     */
+    length(n: number): Assertion;
+
+    /**
+     * Assert property name exists, with optional val.
+     *
+     * @param name
+     * @param val
+     */
+    property(name: string, val?: any): Assertion;
+
+    /**
+     * Assert that string contains str.
+     */
+    contain(...strings: string[]): Assertion;
+    string(str: string): Assertion;
+
+    /**
+     * Assert that the array contains obj.
+     */
+    contain(...objs: any[]): Assertion;
+    string(obj: any): Assertion;
+
+    /**
+     * Assert exact keys or inclusion of keys by using the `.own` modifier.
+     */
+    key(keys: string[]): Assertion;
+    /**
+     * Assert exact keys or inclusion of keys by using the `.own` modifier.
+     */
+    key(...keys: string[]): Assertion;
+    /**
+     * Assert exact keys or inclusion of keys by using the `.own` modifier.
+     */
+    keys(keys: string[]): Assertion;
+    /**
+     * Assert exact keys or inclusion of keys by using the `.own` modifier.
+     */
+    keys(...keys: string[]): Assertion;
+
+    /**
+     * Assert a failure.
+     */
+    fail(message?: string): Assertion;
+  }
+
+  interface Root extends Assertion {
+    not: Not;
+    to: To;
+    only: Only;
+    have: Have;
+    be: Be;
+  }
+
+  interface Be extends Assertion {
+    /**
+     * Checks if the obj exactly equals another.
+     */
+    (obj: any): Assertion;
+
+    an: An;
+  }
+
+  interface An extends Assertion {
+    /**
+     * Assert typeof.
+     */
+    (type: string): Assertion;
+
+    /**
+     * Assert instanceof.
+     */
+    (type: Function): Assertion;
+  }
+
+  interface Not extends Expect.NotBase {
+    to: Expect.ToBase;
+  }
+
+  interface NotBase extends Assertion {
+    be: Be;
+    have: Have;
+    include: Assertion;
+    only: Only;
+  }
+
+  interface To extends Expect.ToBase {
+    not: Expect.NotBase;
+  }
+
+  interface ToBase extends Assertion {
+    be: Be;
+    have: Have;
+    include: Assertion;
+    only: Only;
+  }
+
+  interface Only extends Assertion {
+    have: Have;
+  }
+
+  interface Have extends Assertion {
+    own: Assertion;
+  }
+}
+
+declare module "expect.js" {
+  //@ts-ignore
+  export = expect;
+}

test/support/util.ts

@@ -1,3 +1,4 @@
+/// <reference types="./expectjs" />
 import type { Server } from "../..";
 import {
   io as ioc,
@@ -6,6 +7,7 @@ import {
   SocketOptions,
 } from "socket.io-client";
 import request from "supertest";
+import type { DefaultEventsMap, EventsMap } from "../../lib/typed-events";
 
 const expect = require("expect.js");
 const i = expect.stringify;
@@ -30,11 +32,14 @@ expect.Assertion.prototype.contain = function (...args) {
   return contain.apply(this, args);
 };
 
-export function createClient(
+export function createClient<
+  CTS extends EventsMap = DefaultEventsMap,
+  STC extends EventsMap = DefaultEventsMap
+>(
   io: Server,
   nsp: string = "/",
   opts?: Partial<ManagerOptions & SocketOptions>
-): ClientSocket {
+): ClientSocket<STC, CTS> {
   // @ts-ignore
   const port = io.httpServer.address().port;
   return ioc(`http://localhost:${port}${nsp}`, opts);
@@ -58,6 +63,16 @@ export function successFn(
   return () => success(done, sio, ...clientSockets);
 }
 
+/**
+ * Asserts a condition so that typescript will recognize the assertion!
+ *
+ * Uses expect's `ok` check on condition
+ * @param condition
+ */
+export function assert(condition: any): asserts condition {
+  expect(condition).to.be.ok();
+}
+
 export function getPort(io: Server): number {
   // @ts-ignore
   return io.httpServer.address().port;

test/uws.ts

@@ -7,6 +7,7 @@ import { Server } from "..";
 import { io as ioc, Socket as ClientSocket } from "socket.io-client";
 import request from "supertest";
 import expect from "expect.js";
+import { assert } from "./support/util";
 
 const createPartialDone = (done: (err?: Error) => void, count: number) => {
   let i = 0;
@@ -134,6 +135,8 @@ describe("socket.io with uWebSocket.js-based engine", () => {
     clientWSOnly.on("hello", partialDone);
     clientPollingOnly.on("hello", partialDone);
     clientCustomNamespace.on("hello", shouldNotHappen(done));
+    assert(clientWSOnly.id);
+    assert(clientPollingOnly.id);
 
     io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
     io.of("/").sockets.get(clientPollingOnly.id)!.join("room1");
@@ -148,6 +151,8 @@ describe("socket.io with uWebSocket.js-based engine", () => {
     clientWSOnly.on("hello", partialDone);
     clientPollingOnly.on("hello", partialDone);
     clientCustomNamespace.on("hello", shouldNotHappen(done));
+    assert(clientWSOnly.id);
+    assert(clientPollingOnly.id);
 
     io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
     io.of("/").sockets.get(clientPollingOnly.id)!.join("room2");
@@ -163,6 +168,8 @@ describe("socket.io with uWebSocket.js-based engine", () => {
     clientPollingOnly.on("hello", shouldNotHappen(done));
     clientCustomNamespace.on("hello", shouldNotHappen(done));
 
+    assert(clientWSOnly.id);
+    assert(clientPollingOnly.id);
     io.of("/").sockets.get(clientWSOnly.id)!.join("room1");
     io.of("/").sockets.get(clientPollingOnly.id)!.join("room2");
 
@@ -177,6 +184,9 @@ describe("socket.io with uWebSocket.js-based engine", () => {
     clientPollingOnly.on("hello", partialDone);
     clientCustomNamespace.on("hello", shouldNotHappen(done));
 
+    assert(client.id);
+    assert(clientWSOnly.id);
+    assert(clientPollingOnly.id);
     io.of("/").sockets.get(client.id)!.join("room1");
     io.of("/").sockets.get(clientPollingOnly.id)!.join("room1");
 
@@ -189,6 +199,7 @@ describe("socket.io with uWebSocket.js-based engine", () => {
   it("should not crash when socket is disconnected before the upgrade", (done) => {
     client.on("disconnect", () => done());
 
+    assert(client.id);
     io.of("/").sockets.get(client.id)!.disconnect();
   });