chore(release): 4.3.1

Diff: https://github.com/socketio/socket.io/compare/4.3.0...4.3.1
fix: fix server attachment (#4127 )
2026-01-11 07:58:13 -05:00 · 2021-10-17 00:02:16 +02:00 · 2021-10-16 23:58:55 +02:00 · 2021-10-14 14:59:13 +02:00 · 2021-10-13 18:17:12 +02:00 · 2021-10-12 00:05:10 +02:00
126 changed files with 11994 additions and 36051 deletions
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,12 +12,12 @@ jobs:

    strategy:
      matrix:
-        node-version: [10.x, 12.x, 14.x, 15.x]
+        node-version: [12, 14, 16]

    steps:
      - uses: actions/checkout@v2
      - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v2
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm ci
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,123 @@
+## [4.3.1](https://github.com/socketio/socket.io/compare/4.3.0...4.3.1) (2021-10-16)
+
+
+### Bug Fixes
+
+* fix server attachment ([#4127](https://github.com/socketio/socket.io/issues/4127)) ([0ef2a4d](https://github.com/socketio/socket.io/commit/0ef2a4d02c9350aff163df9cb61aece89c4dac0f))
+
+
+# [4.3.0](https://github.com/socketio/socket.io/compare/4.2.0...4.3.0) (2021-10-14)
+
+
+### Bug Fixes
+
+* **typings:** add name field to cookie option ([#4099](https://github.com/socketio/socket.io/issues/4099)) ([033c5d3](https://github.com/socketio/socket.io/commit/033c5d399a2b985afad32c1e4b0c16d764e248cd))
+* send volatile packets with binary attachments ([dc81fcf](https://github.com/socketio/socket.io/commit/dc81fcf461cfdbb5b34b1a5a96b84373754047d5))
+
+
+### Features
+
+* serve ESM bundle ([60edecb](https://github.com/socketio/socket.io/commit/60edecb3bd33801803cdcba0aefbafa381a2abb3))
+
+
+# [4.2.0](https://github.com/socketio/socket.io/compare/4.1.3...4.2.0) (2021-08-30)
+
+
+### Bug Fixes
+
+* **typings:** allow async listener in typed events ([ccfd8ca](https://github.com/socketio/socket.io/commit/ccfd8caba6d38b7ba6c5114bd8179346ed07671c))
+
+
+### Features
+
+* ignore the query string when serving client JavaScript ([#4024](https://github.com/socketio/socket.io/issues/4024)) ([24fee27](https://github.com/socketio/socket.io/commit/24fee27ba36485308f8e995879c10931532c814e))
+
+
+## [4.1.3](https://github.com/socketio/socket.io/compare/4.1.2...4.1.3) (2021-07-10)
+
+
+### Bug Fixes
+
+* fix io.except() method ([94e27cd](https://github.com/socketio/socket.io/commit/94e27cd072c8a4eeb9636f6ffbb7a21d382f36b0))
+* remove x-sourcemap header ([a4dffc6](https://github.com/socketio/socket.io/commit/a4dffc6527f412d51a786ae5bf2e9080fe1ca63c))
+
+
+## [4.1.2](https://github.com/socketio/socket.io/compare/4.1.1...4.1.2) (2021-05-17)
+
+
+### Bug Fixes
+
+* **typings:** ensure compatibility with TypeScript 3.x ([0cb6ac9](https://github.com/socketio/socket.io/commit/0cb6ac95b49a27483b6f1b6402fa54b35f82e36f))
+* ensure compatibility with previous versions of the adapter ([a2cf248](https://github.com/socketio/socket.io/commit/a2cf2486c366cb62293101c10520c57f6984a3fc))
+
+
+## [4.1.1](https://github.com/socketio/socket.io/compare/4.1.0...4.1.1) (2021-05-11)
+
+
+### Bug Fixes
+
+* **typings:** properly type server-side events ([b84ed1e](https://github.com/socketio/socket.io/commit/b84ed1e41c9053792caf58974c5de9395bfd509f))
+* **typings:** properly type the adapter attribute ([891b187](https://github.com/socketio/socket.io/commit/891b1870e92d1ec38910f03bb839817e2d6be65a))
+
+
+# [4.1.0](https://github.com/socketio/socket.io/compare/4.0.2...4.1.0) (2021-05-11)
+
+
+### Features
+
+* add support for inter-server communication ([93cce05](https://github.com/socketio/socket.io/commit/93cce05fb3faf91f21fa71212275c776aa161107))
+* notify upon namespace creation ([499c892](https://github.com/socketio/socket.io/commit/499c89250d2db1ab7725ab2b74840e188c267c46))
+* add a "connection_error" event ([7096e98](https://github.com/socketio/engine.io/commit/7096e98a02295a62c8ea2aa56461d4875887092d), from `engine.io`)
+* add the "initial_headers" and "headers" events ([2527543](https://github.com/socketio/engine.io/commit/252754353a0e88eb036ebb3082e9d6a9a5f497db), from `engine.io`)
+
+
+### Performance Improvements
+
+* add support for the "wsPreEncoded" writing option ([dc381b7](https://github.com/socketio/socket.io/commit/dc381b72c6b2f8172001dedd84116122e4cc95b3))
+
+
+## [4.0.2](https://github.com/socketio/socket.io/compare/4.0.1...4.0.2) (2021-05-06)
+
+
+### Bug Fixes
+
+* **typings:** make "engine" attribute public ([b81ce4c](https://github.com/socketio/socket.io/commit/b81ce4c9d0b00666361498e2ba5e0d007d5860b8))
+* properly export the Socket class ([d65b6ee](https://github.com/socketio/socket.io/commit/d65b6ee84c8e91deb61c3c1385eb19afa196a909))
+
+
+## [4.0.1](https://github.com/socketio/socket.io/compare/4.0.0...4.0.1) (2021-03-31)
+
+
+### Bug Fixes
+
+* **typings:** add fallback to untyped event listener ([#3834](https://github.com/socketio/socket.io/issues/3834)) ([a11152f](https://github.com/socketio/socket.io/commit/a11152f42b281df83409313962f60f230239c79e))
+* **typings:** update return type from emit ([#3843](https://github.com/socketio/socket.io/issues/3843)) ([1a72ae4](https://github.com/socketio/socket.io/commit/1a72ae4fe27a14cf60916f991a2c94da91d9e54a))
+
+
+# [4.0.0](https://github.com/socketio/socket.io/compare/3.1.2...4.0.0) (2021-03-10)
+
+
+### Bug Fixes
+
+* make io.to(...) immutable ([ac9e8ca](https://github.com/socketio/socket.io/commit/ac9e8ca6c71e00d4af45ee03f590fe56f3951186))
+
+
+### Features
+
+* add some utility methods ([b25495c](https://github.com/socketio/socket.io/commit/b25495c069031674da08e19aed68922c7c7a0e28))
+* add support for typed events ([#3822](https://github.com/socketio/socket.io/issues/3822)) ([0107510](https://github.com/socketio/socket.io/commit/0107510ba8a0f148c78029d8be8919b350feb633))
+* allow to exclude specific rooms when broadcasting ([#3789](https://github.com/socketio/socket.io/issues/3789)) ([7de2e87](https://github.com/socketio/socket.io/commit/7de2e87e888d849eb2dfc5e362af4c9e86044701))
+* allow to pass an array to io.to(...) ([085d1de](https://github.com/socketio/socket.io/commit/085d1de9df909651de8b313cc6f9f253374b702e))
+
+
+## [3.1.2](https://github.com/socketio/socket.io/compare/3.1.1...3.1.2) (2021-02-26)
+
+
+### Bug Fixes
+
+* ignore packets received after disconnection ([494c64e](https://github.com/socketio/socket.io/commit/494c64e44f645cbd24c645f1186d203789e84af0))
+
+
 ## [3.1.1](https://github.com/socketio/socket.io/compare/3.1.0...3.1.1) (2021-02-03)


--- a/Readme.md
+++ b/Readme.md
@@ -1,5 +1,5 @@
 # socket.io
-[![Run on Repl.it](https://repl.it/badge/github/socketio/socket.io)](https://repl.it/github/socketio/socket.io)
+[![Run on Repl.it](https://repl.it/badge/github/socketio/socket.io)](https://replit.com/@socketio/socketio-minimal-example)
 [![Backers on Open Collective](https://opencollective.com/socketio/backers/badge.svg)](#backers) [![Sponsors on Open Collective](https://opencollective.com/socketio/sponsors/badge.svg)](#sponsors)
 [![Build Status](https://github.com/socketio/socket.io/workflows/CI/badge.svg)](https://github.com/socketio/socket.io/actions)
 [![Dependency Status](https://david-dm.org/socketio/socket.io.svg)](https://david-dm.org/socketio/socket.io)
@@ -22,7 +22,7 @@ Some implementations in other languages are also available:
 - [Swift](https://github.com/socketio/socket.io-client-swift)
 - [Dart](https://github.com/rikulo/socket.io-client-dart)
 - [Python](https://github.com/miguelgrinberg/python-socketio)
- [.Net](https://github.com/Quobject/SocketIoClientDotNet)
+- [.NET](https://github.com/doghappy/socket.io-client-csharp)

 Its main features are:

--- a/client-dist/socket.io.esm.min.js
+++ b/client-dist/socket.io.esm.min.js
--- a/client-dist/socket.io.esm.min.js.map
+++ b/client-dist/socket.io.esm.min.js.map
--- a/client-dist/socket.io.js
+++ b/client-dist/socket.io.js
--- a/client-dist/socket.io.js.map
+++ b/client-dist/socket.io.js.map
--- a/client-dist/socket.io.min.js
+++ b/client-dist/socket.io.min.js
--- a/client-dist/socket.io.min.js.map
+++ b/client-dist/socket.io.min.js.map
--- a/client-dist/socket.io.msgpack.min.js
+++ b/client-dist/socket.io.msgpack.min.js
--- a/client-dist/socket.io.msgpack.min.js.map
+++ b/client-dist/socket.io.msgpack.min.js.map
--- a/examples/.gitignore
+++ b/examples/.gitignore
@@ -0,0 +1 @@
+package-lock.json
--- a/examples/angular-todomvc/package-lock.json
+++ b/examples/angular-todomvc/package-lock.json
--- a/examples/angular-todomvc/package.json
+++ b/examples/angular-todomvc/package.json
@@ -21,8 +21,8 @@
    "@angular/platform-browser-dynamic": "~11.0.4",
    "@angular/router": "~11.0.4",
    "rxjs": "~6.6.0",
-    "socket.io": "^3.0.4",
-    "socket.io-client": "^3.0.4",
+    "socket.io": "^4.0.0",
+    "socket.io-client": "^4.0.0",
    "tslib": "^2.0.0",
    "zone.js": "~0.10.2"
  },
--- a/examples/angular-todomvc/server.ts
+++ b/examples/angular-todomvc/server.ts
@@ -1,4 +1,4 @@
-import { Server, Socket } from "socket.io";
+import { Server } from "socket.io";

 const io = new Server(8080, {
  cors: {
@@ -15,7 +15,7 @@ interface Todo {

 let todos: Array<Todo> = [];

-io.on("connect", (socket: Socket) => {
+io.on("connect", (socket) => {
    socket.emit("todos", todos);

    // note: we could also create a CRUD (create/read/update/delete) service for the todo list
--- a/examples/basic-crud-application/README.md
+++ b/examples/basic-crud-application/README.md
@@ -0,0 +1,19 @@
+# Basic CRUD application with Socket.IO
+
+Please read the related [guide](https://socket.io/get-started/basic-crud-application/).
+
+## Running the frontend
+
+```
+cd angular-client
+npm install
+npm start
+```
+
+### Running the server
+
+```
+cd server
+npm install
+npm start
+```
--- a/examples/basic-crud-application/angular-client/.browserslistrc
+++ b/examples/basic-crud-application/angular-client/.browserslistrc
@@ -0,0 +1,17 @@
+# 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.
--- a/examples/basic-crud-application/angular-client/.editorconfig
+++ b/examples/basic-crud-application/angular-client/.editorconfig
@@ -0,0 +1,16 @@
+# Editor configuration, see https://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.ts]
+quote_type = single
+
+[*.md]
+max_line_length = off
+trim_trailing_whitespace = false
--- a/examples/basic-crud-application/angular-client/.gitignore
+++ b/examples/basic-crud-application/angular-client/.gitignore
@@ -0,0 +1,46 @@
+# See http://help.github.com/ignore-files/ for more about ignoring files.
+
+# compiled output
+/dist
+/tmp
+/out-tsc
+# Only exists if Bazel was run
+/bazel-out
+
+# dependencies
+/node_modules
+
+# profiling files
+chrome-profiler-events*.json
+speed-measure-plugin*.json
+
+# IDEs and editors
+/.idea
+.project
+.classpath
+.c9/
+*.launch
+.settings/
+*.sublime-workspace
+
+# IDE - VSCode
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+.history/*
+
+# misc
+/.sass-cache
+/connect.lock
+/coverage
+/libpeerconnection.log
+npm-debug.log
+yarn-error.log
+testem.log
+/typings
+
+# System Files
+.DS_Store
+Thumbs.db
--- a/examples/basic-crud-application/angular-client/README.md
+++ b/examples/basic-crud-application/angular-client/README.md
@@ -0,0 +1,31 @@
+# Angular TodoMVC + Socket.IO
+
+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)
+
+## 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.
+
+## Code scaffolding
+
+Run `ng generate component component-name` to generate a new component. You can also use `ng generate directive|pipe|service|class|guard|interface|enum|module`.
+
+## 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.
+
+## Running unit tests
+
+Run `ng test` to execute the unit tests via [Karma](https://karma-runner.github.io).
+
+## Running end-to-end tests
+
+Run `ng e2e` to execute the end-to-end tests via [Protractor](http://www.protractortest.org/).
+
+## Further help
+
+To get more help on the Angular CLI use `ng help` or go check out the [Angular CLI Overview and Command Reference](https://angular.io/cli) page.
--- a/examples/basic-crud-application/angular-client/angular.json
+++ b/examples/basic-crud-application/angular-client/angular.json
@@ -0,0 +1,128 @@
+{
+  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
+  "version": 1,
+  "newProjectRoot": "projects",
+  "projects": {
+    "angular-todomvc": {
+      "projectType": "application",
+      "schematics": {
+        "@schematics/angular:application": {
+          "strict": true
+        }
+      },
+      "root": "",
+      "sourceRoot": "src",
+      "prefix": "app",
+      "architect": {
+        "build": {
+          "builder": "@angular-devkit/build-angular:browser",
+          "options": {
+            "outputPath": "dist/angular-todomvc",
+            "index": "src/index.html",
+            "main": "src/main.ts",
+            "polyfills": "src/polyfills.ts",
+            "tsConfig": "tsconfig.app.json",
+            "aot": true,
+            "assets": [
+              "src/favicon.ico",
+              "src/assets"
+            ],
+            "styles": [
+              "src/styles.css"
+            ],
+            "scripts": []
+          },
+          "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",
+                  "maximumWarning": "500kb",
+                  "maximumError": "1mb"
+                },
+                {
+                  "type": "anyComponentStyle",
+                  "maximumWarning": "2kb",
+                  "maximumError": "4kb"
+                }
+              ]
+            }
+          }
+        },
+        "serve": {
+          "builder": "@angular-devkit/build-angular:dev-server",
+          "options": {
+            "browserTarget": "angular-todomvc:build"
+          },
+          "configurations": {
+            "production": {
+              "browserTarget": "angular-todomvc:build:production"
+            }
+          }
+        },
+        "extract-i18n": {
+          "builder": "@angular-devkit/build-angular:extract-i18n",
+          "options": {
+            "browserTarget": "angular-todomvc:build"
+          }
+        },
+        "test": {
+          "builder": "@angular-devkit/build-angular:karma",
+          "options": {
+            "main": "src/test.ts",
+            "polyfills": "src/polyfills.ts",
+            "tsConfig": "tsconfig.spec.json",
+            "karmaConfig": "karma.conf.js",
+            "assets": [
+              "src/favicon.ico",
+              "src/assets"
+            ],
+            "styles": [
+              "src/styles.css"
+            ],
+            "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"
+}
--- a/examples/basic-crud-application/angular-client/assets/demo.gif
+++ b/examples/basic-crud-application/angular-client/assets/demo.gif
--- a/examples/basic-crud-application/angular-client/e2e/protractor.conf.js
+++ b/examples/basic-crud-application/angular-client/e2e/protractor.conf.js
@@ -0,0 +1,37 @@
+// @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
+      }
+    }));
+  }
+};
--- a/examples/basic-crud-application/angular-client/e2e/src/app.e2e-spec.ts
+++ b/examples/basic-crud-application/angular-client/e2e/src/app.e2e-spec.ts
@@ -0,0 +1,23 @@
+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));
+  });
+});
--- a/examples/basic-crud-application/angular-client/e2e/src/app.po.ts
+++ b/examples/basic-crud-application/angular-client/e2e/src/app.po.ts
@@ -0,0 +1,11 @@
+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();
+  }
+}
--- a/examples/basic-crud-application/angular-client/e2e/tsconfig.json
+++ b/examples/basic-crud-application/angular-client/e2e/tsconfig.json
@@ -0,0 +1,13 @@
+/* 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"
+    ]
+  }
+}
--- a/examples/basic-crud-application/angular-client/karma.conf.js
+++ b/examples/basic-crud-application/angular-client/karma.conf.js
@@ -0,0 +1,44 @@
+// 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
+  });
+};
--- a/examples/basic-crud-application/angular-client/package.json
+++ b/examples/basic-crud-application/angular-client/package.json
@@ -0,0 +1,46 @@
+{
+  "name": "angular-todomvc",
+  "version": "0.0.0",
+  "scripts": {
+    "ng": "ng",
+    "start": "ng serve",
+    "build": "ng build",
+    "test": "ng test",
+    "lint": "ng lint",
+    "e2e": "ng e2e"
+  },
+  "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"
+  },
+  "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"
+  }
+}
--- a/examples/basic-crud-application/angular-client/src/app/app.component.css
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.css
--- a/examples/basic-crud-application/angular-client/src/app/app.component.html
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.html
@@ -0,0 +1,23 @@
+<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()">
+  </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)">
+    <ul class="todo-list">
+      <li *ngFor="let todo of todoStore.todos" [class.completed]="todo.completed" [class.editing]="todo.editing">
+        <div class="view">
+          <input class="toggle" type="checkbox" (click)="toggleCompletion(todo)" [checked]="todo.completed">
+          <label (dblclick)="editTodo(todo)">{{todo.title}}</label>
+          <button class="destroy" (click)="remove(todo)"></button>
+        </div>
+        <input class="edit" *ngIf="todo.editing" [value]="todo.title" #editedtodo (blur)="stopEditing(todo, editedtodo.value)" (keyup.enter)="updateEditingTodo(todo, editedtodo.value)" (keyup.escape)="cancelEditingTodo(todo)">
+      </li>
+    </ul>
+  </section>
+  <footer class="footer" *ngIf="todoStore.todos.length > 0">
+    <span class="todo-count"><strong>{{todoStore.getRemaining().length}}</strong> {{todoStore.getRemaining().length == 1 ? 'item' : 'items'}} left</span>
+    <button class="clear-completed" *ngIf="todoStore.getCompleted().length > 0" (click)="removeCompleted()">Clear completed</button>
+  </footer>
+</section>
--- a/examples/basic-crud-application/angular-client/src/app/app.component.spec.ts
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.spec.ts
@@ -0,0 +1,31 @@
+import { TestBed } from '@angular/core/testing';
+import { AppComponent } from './app.component';
+
+describe('AppComponent', () => {
+  beforeEach(async () => {
+    await TestBed.configureTestingModule({
+      declarations: [
+        AppComponent
+      ],
+    }).compileComponents();
+  });
+
+  it('should create the app', () => {
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.componentInstance;
+    expect(app).toBeTruthy();
+  });
+
+  it(`should have as title 'angular-todomvc'`, () => {
+    const fixture = TestBed.createComponent(AppComponent);
+    const app = fixture.componentInstance;
+    expect(app.title).toEqual('angular-todomvc');
+  });
+
+  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!');
+  });
+});
--- a/examples/basic-crud-application/angular-client/src/app/app.component.ts
+++ b/examples/basic-crud-application/angular-client/src/app/app.component.ts
@@ -0,0 +1,59 @@
+import { Component } from '@angular/core';
+import { TodoStore, Todo } from './store';
+
+@Component({
+  selector: 'app-root',
+  templateUrl: './app.component.html',
+  styleUrls: ['./app.component.css']
+})
+export class AppComponent {
+  todoStore: TodoStore;
+  newTodoText = '';
+
+  constructor(todoStore: TodoStore) {
+    this.todoStore = todoStore;
+  }
+
+  stopEditing(todo: Todo, editedTitle: string) {
+    todo.title = editedTitle;
+    todo.editing = false;
+  }
+
+  cancelEditingTodo(todo: Todo) {
+    todo.editing = false;
+  }
+
+  updateEditingTodo(todo: Todo, editedTitle: string) {
+    editedTitle = editedTitle.trim();
+    todo.editing = false;
+
+    if (editedTitle.length === 0) {
+      return this.todoStore.remove(todo);
+    }
+
+    todo.title = editedTitle;
+  }
+
+  editTodo(todo: Todo) {
+    todo.editing = true;
+  }
+
+  removeCompleted() {
+    this.todoStore.removeCompleted();
+  }
+
+  toggleCompletion(todo: Todo) {
+    this.todoStore.toggleCompletion(todo);
+  }
+
+  remove(todo: Todo){
+    this.todoStore.remove(todo);
+  }
+
+  addTodo() {
+    if (this.newTodoText.trim().length) {
+      this.todoStore.add(this.newTodoText);
+      this.newTodoText = '';
+    }
+  }
+}
--- a/examples/basic-crud-application/angular-client/src/app/app.module.ts
+++ b/examples/basic-crud-application/angular-client/src/app/app.module.ts
@@ -0,0 +1,19 @@
+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 { }
--- a/examples/basic-crud-application/angular-client/src/app/store.ts
+++ b/examples/basic-crud-application/angular-client/src/app/store.ts
@@ -0,0 +1,140 @@
+import { io, Socket } from "socket.io-client";
+import { ClientEvents, ServerEvents } from "../../../server/lib/events";
+import { environment } from '../environments/environment';
+
+export interface Todo {
+  id: string,
+  title: string,
+  completed: boolean,
+  editing: boolean,
+  synced: boolean
+}
+
+const mapTodo = (todo: any) => {
+  return {
+    ...todo,
+    editing: false,
+    synced: true
+  }
+}
+
+export class TodoStore {
+  public todos: Array<Todo> = [];
+  private socket: Socket<ServerEvents, ClientEvents>;
+
+  constructor() {
+    this.socket = io(environment.serverUrl);
+
+    this.socket.on("connect", () => {
+      this.socket.emit("todo:list", (res) => {
+        if ("error" in res) {
+          // handle the error
+          return;
+        }
+        this.todos = res.data.map(mapTodo);
+      });
+    });
+
+    this.socket.on("todo:created", (todo) => {
+      this.todos.push(mapTodo(todo));
+    });
+
+    this.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;
+      }
+    });
+
+    this.socket.on("todo:deleted", (id) => {
+      const index = this.todos.findIndex(t => {
+        return t.id === id
+      });
+      if (index !== -1) {
+        this.todos.splice(index, 1);
+      }
+    })
+  }
+
+  private getWithCompleted(completed: boolean) {
+    return this.todos.filter((todo: Todo) => todo.completed === completed);
+  }
+
+  allCompleted() {
+    return this.todos.length === this.getCompleted().length;
+  }
+
+  setAllTo(completed: boolean) {
+    this.todos.forEach(todo => {
+      todo.completed = completed;
+      todo.synced = false;
+      this.socket.emit("todo:update", todo, (res) => {
+        if (res && "error" in res) {
+          // handle the error
+          return;
+        }
+        todo.synced = true;
+      });
+    });
+  }
+
+  removeCompleted() {
+    this.getCompleted().forEach((todo) => {
+      this.socket.emit("todo:delete", todo.id, (res) => {
+        if (res && "error" in res) {
+          // handle the error
+        }
+      });
+    })
+    this.todos = this.getRemaining();
+  }
+
+  getRemaining() {
+    return this.getWithCompleted(false);
+  }
+
+  getCompleted() {
+    return this.getWithCompleted(true);
+  }
+
+  toggleCompletion(todo: Todo) {
+    todo.completed = !todo.completed;
+    todo.synced = false;
+    this.socket.emit("todo:update", todo, (res) => {
+      if (res && "error" in res) {
+        // handle the error
+        return;
+      }
+      todo.synced = true;
+    })
+  }
+
+  remove(todo: Todo) {
+    this.todos.splice(this.todos.indexOf(todo), 1);
+    this.socket.emit("todo:delete", todo.id, (res) => {
+      if (res && "error" in res) {
+        // handle the error
+      }
+    });
+  }
+
+  add(title: string) {
+    this.socket.emit("todo:create", { title, completed: false }, (res) => {
+      if ("error" in res) {
+        // handle the error
+        return;
+      }
+      this.todos.push({
+        id: res.data,
+        title,
+        completed: false,
+        editing: false,
+        synced: true
+      });
+    });
+  }
+}
+
--- a/examples/basic-crud-application/angular-client/src/assets/.gitkeep
+++ b/examples/basic-crud-application/angular-client/src/assets/.gitkeep
--- a/examples/basic-crud-application/angular-client/src/environments/environment.prod.ts
+++ b/examples/basic-crud-application/angular-client/src/environments/environment.prod.ts
@@ -0,0 +1,4 @@
+export const environment = {
+  production: true,
+  serverUrl: "https://my-custom-domain.com"
+};
--- a/examples/basic-crud-application/angular-client/src/environments/environment.ts
+++ b/examples/basic-crud-application/angular-client/src/environments/environment.ts
@@ -0,0 +1,17 @@
+// 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"
+};
+
+/*
+ * 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.
--- a/examples/basic-crud-application/angular-client/src/favicon.ico
+++ b/examples/basic-crud-application/angular-client/src/favicon.ico
--- a/examples/basic-crud-application/angular-client/src/index.html
+++ b/examples/basic-crud-application/angular-client/src/index.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <title>Angular Todo MVC</title>
+  <base href="/">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <link rel="icon" type="image/x-icon" href="favicon.ico">
+</head>
+<body>
+  <app-root></app-root>
+</body>
+</html>
--- a/examples/basic-crud-application/angular-client/src/main.ts
+++ b/examples/basic-crud-application/angular-client/src/main.ts
@@ -0,0 +1,12 @@
+import { enableProdMode } from '@angular/core';
+import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
+
+import { AppModule } from './app/app.module';
+import { environment } from './environments/environment';
+
+if (environment.production) {
+  enableProdMode();
+}
+
+platformBrowserDynamic().bootstrapModule(AppModule)
+  .catch(err => console.error(err));
--- a/examples/basic-crud-application/angular-client/src/polyfills.ts
+++ b/examples/basic-crud-application/angular-client/src/polyfills.ts
@@ -0,0 +1,63 @@
+/**
+ * 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
+ */
--- a/examples/basic-crud-application/angular-client/src/styles.css
+++ b/examples/basic-crud-application/angular-client/src/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;
+  }
+}
--- a/examples/basic-crud-application/angular-client/src/test.ts
+++ b/examples/basic-crud-application/angular-client/src/test.ts
@@ -0,0 +1,25 @@
+// 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);
--- a/examples/basic-crud-application/angular-client/tsconfig.app.json
+++ b/examples/basic-crud-application/angular-client/tsconfig.app.json
@@ -0,0 +1,15 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./out-tsc/app",
+    "types": []
+  },
+  "files": [
+    "src/main.ts",
+    "src/polyfills.ts"
+  ],
+  "include": [
+    "src/**/*.d.ts"
+  ]
+}
--- a/examples/basic-crud-application/angular-client/tsconfig.json
+++ b/examples/basic-crud-application/angular-client/tsconfig.json
@@ -0,0 +1,29 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "baseUrl": "./",
+    "outDir": "./dist/out-tsc",
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "sourceMap": true,
+    "declaration": false,
+    "downlevelIteration": true,
+    "experimentalDecorators": true,
+    "moduleResolution": "node",
+    "importHelpers": true,
+    "target": "es2015",
+    "module": "es2020",
+    "lib": [
+      "es2018",
+      "dom"
+    ]
+  },
+  "angularCompilerOptions": {
+    "strictInjectionParameters": true,
+    "strictInputAccessModifiers": true,
+    "strictTemplates": true
+  }
+}
--- a/examples/basic-crud-application/angular-client/tsconfig.spec.json
+++ b/examples/basic-crud-application/angular-client/tsconfig.spec.json
@@ -0,0 +1,18 @@
+/* To learn more about this file see: https://angular.io/config/tsconfig. */
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "./out-tsc/spec",
+    "types": [
+      "jasmine"
+    ]
+  },
+  "files": [
+    "src/test.ts",
+    "src/polyfills.ts"
+  ],
+  "include": [
+    "src/**/*.spec.ts",
+    "src/**/*.d.ts"
+  ]
+}
--- a/examples/basic-crud-application/angular-client/tslint.json
+++ b/examples/basic-crud-application/angular-client/tslint.json
@@ -0,0 +1,152 @@
+{
+  "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"
+    ]
+  }
+}
--- a/examples/basic-crud-application/server/lib/app.ts
+++ b/examples/basic-crud-application/server/lib/app.ts
@@ -0,0 +1,35 @@
+import { Server as HttpServer } from "http";
+import { Server, ServerOptions } from "socket.io";
+import { ClientEvents, ServerEvents } from "./events";
+import { TodoRepository } from "./todo-management/todo.repository";
+import createTodoHandlers from "./todo-management/todo.handlers";
+
+export interface Components {
+  todoRepository: TodoRepository;
+}
+
+export function createApplication(
+  httpServer: HttpServer,
+  components: Components,
+  serverOptions: Partial<ServerOptions> = {}
+): Server<ClientEvents, ServerEvents> {
+  const io = new Server<ClientEvents, ServerEvents>(httpServer, serverOptions);
+
+  const {
+    createTodo,
+    readTodo,
+    updateTodo,
+    deleteTodo,
+    listTodo,
+  } = createTodoHandlers(components);
+
+  io.on("connection", (socket) => {
+    socket.on("todo:create", createTodo);
+    socket.on("todo:read", readTodo);
+    socket.on("todo:update", updateTodo);
+    socket.on("todo:delete", deleteTodo);
+    socket.on("todo:list", listTodo);
+  });
+
+  return io;
+}
--- a/examples/basic-crud-application/server/lib/events.ts
+++ b/examples/basic-crud-application/server/lib/events.ts
@@ -0,0 +1,37 @@
+import { Todo, TodoID } from "./todo-management/todo.repository";
+import { ValidationErrorItem } from "joi";
+
+interface Error {
+  error: string;
+  errorDetails?: ValidationErrorItem[];
+}
+
+interface Success<T> {
+  data: T;
+}
+
+export type Response<T> = Error | Success<T>;
+
+export interface ServerEvents {
+  "todo:created": (todo: Todo) => void;
+  "todo:updated": (todo: Todo) => void;
+  "todo:deleted": (id: TodoID) => void;
+}
+
+export interface ClientEvents {
+  "todo:list": (callback: (res: Response<Todo[]>) => void) => void;
+
+  "todo:create": (
+    payload: Omit<Todo, "id">,
+    callback: (res: Response<TodoID>) => void
+  ) => void;
+
+  "todo:read": (id: TodoID, callback: (res: Response<Todo>) => void) => void;
+
+  "todo:update": (
+    payload: Todo,
+    callback: (res?: Response<void>) => void
+  ) => void;
+
+  "todo:delete": (id: TodoID, callback: (res?: Response<void>) => void) => void;
+}
--- a/examples/basic-crud-application/server/lib/index.ts
+++ b/examples/basic-crud-application/server/lib/index.ts
@@ -0,0 +1,19 @@
+import { createServer } from "http";
+import { createApplication } from "./app";
+import { InMemoryTodoRepository } from "./todo-management/todo.repository";
+
+const httpServer = createServer();
+
+createApplication(
+  httpServer,
+  {
+    todoRepository: new InMemoryTodoRepository(),
+  },
+  {
+    cors: {
+      origin: ["http://localhost:4200"],
+    },
+  }
+);
+
+httpServer.listen(3000);
--- a/examples/basic-crud-application/server/lib/todo-management/todo.handlers.ts
+++ b/examples/basic-crud-application/server/lib/todo-management/todo.handlers.ts
@@ -0,0 +1,159 @@
+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 { Socket } from "socket.io";
+
+const idSchema = Joi.string().guid({
+  version: "uuidv4",
+});
+
+const todoSchema = Joi.object({
+  id: idSchema.alter({
+    create: (schema) => schema.forbidden(),
+    update: (schema) => schema.required(),
+  }),
+  title: Joi.string().max(256).required(),
+  completed: Joi.boolean().required(),
+});
+
+export default function (components: Components) {
+  const { todoRepository } = components;
+  return {
+    createTodo: async function (
+      payload: Omit<Todo, "id">,
+      callback: (res: Response<TodoID>) => void
+    ) {
+      // @ts-ignore
+      const socket: Socket<ClientEvents, ServerEvents> = this;
+
+      // validate the payload
+      const { error, value } = todoSchema.tailor("create").validate(payload, {
+        abortEarly: false,
+        stripUnknown: true,
+      });
+
+      if (error) {
+        return callback({
+          error: Errors.INVALID_PAYLOAD,
+          errorDetails: mapErrorDetails(error.details),
+        });
+      }
+
+      value.id = uuid();
+
+      // persist the entity
+      try {
+        await todoRepository.save(value);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      // acknowledge the creation
+      callback({
+        data: value.id,
+      });
+
+      // notify the other users
+      socket.broadcast.emit("todo:created", value);
+    },
+
+    readTodo: async function (
+      id: TodoID,
+      callback: (res: Response<Todo>) => void
+    ) {
+      const { error } = idSchema.validate(id);
+
+      if (error) {
+        return callback({
+          error: Errors.ENTITY_NOT_FOUND,
+        });
+      }
+
+      try {
+        const todo = await todoRepository.findById(id);
+        callback({
+          data: todo,
+        });
+      } catch (e) {
+        callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+    },
+
+    updateTodo: async function (
+      payload: Todo,
+      callback: (res?: Response<void>) => void
+    ) {
+      // @ts-ignore
+      const socket: Socket<ClientEvents, ServerEvents> = this;
+
+      const { error, value } = todoSchema.tailor("update").validate(payload, {
+        abortEarly: false,
+        stripUnknown: true,
+      });
+
+      if (error) {
+        return callback({
+          error: Errors.INVALID_PAYLOAD,
+          errorDetails: mapErrorDetails(error.details),
+        });
+      }
+
+      try {
+        await todoRepository.save(value);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      callback();
+      socket.broadcast.emit("todo:updated", value);
+    },
+
+    deleteTodo: async function (
+      id: TodoID,
+      callback: (res?: Response<void>) => void
+    ) {
+      // @ts-ignore
+      const socket: Socket<ClientEvents, ServerEvents> = this;
+
+      const { error } = idSchema.validate(id);
+
+      if (error) {
+        return callback({
+          error: Errors.ENTITY_NOT_FOUND,
+        });
+      }
+
+      try {
+        await todoRepository.deleteById(id);
+      } catch (e) {
+        return callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+
+      callback();
+      socket.broadcast.emit("todo:deleted", id);
+    },
+
+    listTodo: async function (callback: (res: Response<Todo[]>) => void) {
+      try {
+        callback({
+          data: await todoRepository.findAll(),
+        });
+      } catch (e) {
+        callback({
+          error: sanitizeErrorMessage(e),
+        });
+      }
+    },
+  };
+}
--- a/examples/basic-crud-application/server/lib/todo-management/todo.repository.ts
+++ b/examples/basic-crud-application/server/lib/todo-management/todo.repository.ts
@@ -0,0 +1,49 @@
+import { Errors } from "../util";
+
+abstract class CrudRepository<T, ID> {
+  abstract findAll(): Promise<T[]>;
+  abstract findById(id: ID): Promise<T>;
+  abstract save(entity: T): Promise<void>;
+  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 {
+  private readonly todos: Map<TodoID, Todo> = new Map();
+
+  findAll(): Promise<Todo[]> {
+    const entities = Array.from(this.todos.values());
+    return Promise.resolve(entities);
+  }
+
+  findById(id: TodoID): Promise<Todo> {
+    if (this.todos.has(id)) {
+      return Promise.resolve(this.todos.get(id)!);
+    } else {
+      return Promise.reject(Errors.ENTITY_NOT_FOUND);
+    }
+  }
+
+  save(entity: Todo): Promise<void> {
+    this.todos.set(entity.id, entity);
+    return Promise.resolve();
+  }
+
+  deleteById(id: TodoID): Promise<void> {
+    const deleted = this.todos.delete(id);
+    if (deleted) {
+      return Promise.resolve();
+    } else {
+      return Promise.reject(Errors.ENTITY_NOT_FOUND);
+    }
+  }
+}
--- a/examples/basic-crud-application/server/lib/util.ts
+++ b/examples/basic-crud-application/server/lib/util.ts
@@ -0,0 +1,24 @@
+import { ValidationErrorItem } from "joi";
+
+export enum Errors {
+  ENTITY_NOT_FOUND = "entity not found",
+  INVALID_PAYLOAD = "invalid payload",
+}
+
+const errorValues: string[] = Object.values(Errors);
+
+export function sanitizeErrorMessage(message: string) {
+  if (errorValues.includes(message)) {
+    return message;
+  } else {
+    return "an unknown error has occurred";
+  }
+}
+
+export function mapErrorDetails(details: ValidationErrorItem[]) {
+  return details.map((item) => ({
+    message: item.message,
+    path: item.path,
+    type: item.type,
+  }));
+}
--- a/examples/basic-crud-application/server/package.json
+++ b/examples/basic-crud-application/server/package.json
@@ -0,0 +1,37 @@
+{
+  "name": "basic-crud-server",
+  "version": "0.0.1",
+  "description": "Server for the Basic CRUD Socket.IO example",
+  "main": "dist/lib/index.js",
+  "scripts": {
+    "start": "ts-node lib/index.ts",
+    "build": "tsc",
+    "test": "nyc mocha --require ts-node/register test/**/*.ts"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/socketio/socket.io.git"
+  },
+  "author": "Damien Arrachequesne <damien.arrachequesne@gmail.com>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/socketio/socket.io/issues"
+  },
+  "homepage": "https://github.com/socketio/socket.io#readme",
+  "dependencies": {
+    "joi": "^17.4.0",
+    "socket.io": "^4.0.1",
+    "uuid": "^8.3.2"
+  },
+  "devDependencies": {
+    "@types/mocha": "^8.2.3",
+    "@types/chai": "^4.2.16",
+    "@types/uuid": "^8.3.0",
+    "chai": "^4.3.4",
+    "mocha": "^8.3.2",
+    "nyc": "^15.1.0",
+    "socket.io-client": "^4.0.1",
+    "ts-node": "^9.1.1",
+    "typescript": "^4.2.4"
+  }
+}
--- a/examples/basic-crud-application/server/test/todo-management/todo.tests.ts
+++ b/examples/basic-crud-application/server/test/todo-management/todo.tests.ts
@@ -0,0 +1,309 @@
+import { createApplication } from "../../lib/app";
+import { createServer, Server } from "http";
+import {
+  InMemoryTodoRepository,
+  TodoRepository,
+} from "../../lib/todo-management/todo.repository";
+import { AddressInfo } from "net";
+import { io, Socket } from "socket.io-client";
+import { ClientEvents, ServerEvents } from "../../lib/events";
+import { expect } from "chai";
+
+const createPartialDone = (count: number, done: () => void) => {
+  let i = 0;
+  return () => {
+    if (++i === count) {
+      done();
+    }
+  };
+};
+
+describe("todo management", () => {
+  let httpServer: Server,
+    socket: Socket<ServerEvents, ClientEvents>,
+    otherSocket: Socket<ServerEvents, ClientEvents>,
+    todoRepository: TodoRepository;
+
+  beforeEach((done) => {
+    const partialDone = createPartialDone(2, done);
+
+    httpServer = createServer();
+    todoRepository = new InMemoryTodoRepository();
+
+    createApplication(httpServer, {
+      todoRepository,
+    });
+
+    httpServer.listen(() => {
+      const port = (httpServer.address() as AddressInfo).port;
+      socket = io(`http://localhost:${port}`);
+      socket.on("connect", partialDone);
+
+      otherSocket = io(`http://localhost:${port}`);
+      otherSocket.on("connect", partialDone);
+    });
+  });
+
+  afterEach(() => {
+    httpServer.close();
+    socket.disconnect();
+    otherSocket.disconnect();
+  });
+
+  describe("create todo", () => {
+    it("should create a todo entity", (done) => {
+      const partialDone = createPartialDone(2, done);
+
+      socket.emit(
+        "todo:create",
+        {
+          title: "lorem ipsum",
+          completed: false,
+        },
+        async (res) => {
+          if ("error" in res) {
+            return done(new Error("should not happen"));
+          }
+          expect(res.data).to.be.a("string");
+
+          const storedEntity = await todoRepository.findById(res.data);
+          expect(storedEntity).to.eql({
+            id: res.data,
+            title: "lorem ipsum",
+            completed: false,
+          });
+
+          partialDone();
+        }
+      );
+
+      otherSocket.on("todo:created", (todo) => {
+        expect(todo.id).to.be.a("string");
+        expect(todo.title).to.eql("lorem ipsum");
+        expect(todo.completed).to.eql(false);
+        partialDone();
+      });
+    });
+
+    it("should fail with an invalid entity", (done) => {
+      const incompleteTodo = {
+        completed: "false",
+        description: true,
+      };
+      // @ts-ignore
+      socket.emit("todo:create", incompleteTodo, (res) => {
+        if (!("error" in res)) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.error).to.eql("invalid payload");
+        expect(res.errorDetails).to.eql([
+          {
+            message: '"title" is required',
+            path: ["title"],
+            type: "any.required",
+          },
+        ]);
+        done();
+      });
+
+      otherSocket.on("todo:created", () => {
+        done(new Error("should not happen"));
+      });
+    });
+  });
+
+  describe("read todo", () => {
+    it("should return a todo entity", (done) => {
+      todoRepository.save({
+        id: "254dbf85-f5b9-4675-b913-acab5d600884",
+        title: "lorem ipsum",
+        completed: true,
+      });
+
+      socket.emit(
+        "todo:read",
+        "254dbf85-f5b9-4675-b913-acab5d600884",
+        (res) => {
+          if ("error" in res) {
+            return done(new Error("should not happen"));
+          }
+          expect(res.data.id).to.eql("254dbf85-f5b9-4675-b913-acab5d600884");
+          expect(res.data.title).to.eql("lorem ipsum");
+          expect(res.data.completed).to.eql(true);
+          done();
+        }
+      );
+    });
+
+    it("should fail with an invalid ID", (done) => {
+      socket.emit("todo:read", "123", (res) => {
+        if ("error" in res) {
+          expect(res.error).to.eql("entity not found");
+          done();
+        } else {
+          done(new Error("should not happen"));
+        }
+      });
+    });
+
+    it("should fail with an unknown entity", (done) => {
+      socket.emit(
+        "todo:read",
+        "6edcf81e-7049-40e0-8497-9cdd52414f75",
+        (res) => {
+          if ("error" in res) {
+            expect(res.error).to.eql("entity not found");
+            done();
+          } else {
+            done(new Error("should not happen"));
+          }
+        }
+      );
+    });
+  });
+
+  describe("update todo", () => {
+    it("should update a todo entity", (done) => {
+      const partialDone = createPartialDone(2, done);
+
+      todoRepository.save({
+        id: "c7790b35-6bbb-45dd-8d67-a281ca407b43",
+        title: "lorem ipsum",
+        completed: true,
+      });
+
+      socket.emit(
+        "todo:update",
+        {
+          id: "c7790b35-6bbb-45dd-8d67-a281ca407b43",
+          title: "dolor sit amet",
+          completed: true,
+        },
+        async () => {
+          const storedEntity = await todoRepository.findById(
+            "c7790b35-6bbb-45dd-8d67-a281ca407b43"
+          );
+          expect(storedEntity).to.eql({
+            id: "c7790b35-6bbb-45dd-8d67-a281ca407b43",
+            title: "dolor sit amet",
+            completed: true,
+          });
+          partialDone();
+        }
+      );
+
+      otherSocket.on("todo:updated", (todo) => {
+        expect(todo.title).to.eql("dolor sit amet");
+        expect(todo.completed).to.eql(true);
+        partialDone();
+      });
+    });
+
+    it("should fail with an invalid entity", (done) => {
+      const incompleteTodo = {
+        id: "123",
+        completed: "false",
+        description: true,
+      };
+      // @ts-ignore
+      socket.emit("todo:update", incompleteTodo, (res) => {
+        if (!(res && "error" in res)) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.error).to.eql("invalid payload");
+        expect(res.errorDetails).to.eql([
+          {
+            message: '"id" must be a valid GUID',
+            path: ["id"],
+            type: "string.guid",
+          },
+          {
+            message: '"title" is required',
+            path: ["title"],
+            type: "any.required",
+          },
+        ]);
+        done();
+      });
+
+      otherSocket.on("todo:updated", () => {
+        done(new Error("should not happen"));
+      });
+    });
+  });
+
+  describe("delete todo", () => {
+    it("should delete a todo entity", (done) => {
+      const partialDone = createPartialDone(2, done);
+      const id = "58960ab2-4e78-4ced-8079-134f12179d46";
+
+      todoRepository.save({
+        id,
+        title: "lorem ipsum",
+        completed: true,
+      });
+
+      socket.emit("todo:delete", id, async () => {
+        try {
+          await todoRepository.findById(id);
+        } catch (e) {
+          partialDone();
+        }
+      });
+
+      otherSocket.on("todo:deleted", (id) => {
+        expect(id).to.eql("58960ab2-4e78-4ced-8079-134f12179d46");
+        partialDone();
+      });
+    });
+
+    it("should fail with an invalid ID", (done) => {
+      socket.emit("todo:delete", "123", (res) => {
+        if (!(res && "error" in res)) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.error).to.eql("entity not found");
+        done();
+      });
+
+      otherSocket.on("todo:deleted", () => {
+        done(new Error("should not happen"));
+      });
+    });
+  });
+
+  describe("list todo", () => {
+    it("should return a list of entities", (done) => {
+      todoRepository.save({
+        id: "d445db6d-9d55-4ff2-88ae-bd1f81c299d2",
+        title: "lorem ipsum",
+        completed: false,
+      });
+
+      todoRepository.save({
+        id: "5f56fb59-a887-4984-93bf-eb39b4170a35",
+        title: "dolor sit amet",
+        completed: true,
+      });
+
+      socket.emit("todo:list", (res) => {
+        if ("error" in res) {
+          return done(new Error("should not happen"));
+        }
+        expect(res.data).to.eql([
+          {
+            id: "d445db6d-9d55-4ff2-88ae-bd1f81c299d2",
+            title: "lorem ipsum",
+            completed: false,
+          },
+          {
+            id: "5f56fb59-a887-4984-93bf-eb39b4170a35",
+            title: "dolor sit amet",
+            completed: true,
+          },
+        ]);
+        done();
+      });
+    });
+  });
+});
--- a/examples/basic-crud-application/server/tsconfig.json
+++ b/examples/basic-crud-application/server/tsconfig.json
@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "outDir": "./dist",
+    "module": "commonjs",
+    "target": "es2017",
+    "strict": true
+  },
+  "include": [
+    "./lib/**/*"
+  ]
+}
--- a/examples/chat/package-lock.json
+++ b/examples/chat/package-lock.json
@@ -1,499 +0,0 @@
-{
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-      "requires": {
-        "mime-types": "~2.1.24",
-        "negotiator": "0.6.2"
-      }
-    },
-    "array-flatten": {
-      "version": "1.1.1",
-      "resolved": "https://registry.npmjs.org/array-flatten/-/array-flatten-1.1.1.tgz",
-      "integrity": "sha1-ml9pkFGx5wczKPKgCJaLZOopVdI="
-    },
-    "base64id": {
-      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/base64id/-/base64id-2.0.0.tgz",
-      "integrity": "sha512-lGe34o6EHj9y3Kts9R4ZYs/Gr+6N7MCaMlIFA3F1R2O5/m7K06AxfSeO5530PEERE6/WyEg3lsuyw4GHlPZHog=="
-    },
-    "body-parser": {
-      "version": "1.19.0",
-      "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.19.0.tgz",
-      "integrity": "sha512-dhEPs72UPbDnAQJ9ZKMNTP6ptJaionhP5cBb541nXPlW60Jepo9RV/a4fX4XWW9CuFNK22krhrj1+rgzifNCsw==",
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-        "content-type": "~1.0.4",
-        "debug": "2.6.9",
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-        "raw-body": "2.4.0",
-        "type-is": "~1.6.17"
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-    "bytes": {
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-}
--- a/examples/chat/package.json
+++ b/examples/chat/package.json
@@ -8,7 +8,7 @@
  "license": "BSD",
  "dependencies": {
    "express": "~4.17.1",
-    "socket.io": "^3.0.0"
+    "socket.io": "^4.0.0"
  },
  "scripts": {
    "start": "node index.js"
--- a/examples/chat/public/main.js
+++ b/examples/chat/public/main.js
@@ -72,7 +72,7 @@ $(function() {
  }

  // Adds the visual chat message to the message list
-  const addChatMessage = (data, options) => {
+  const addChatMessage = (data, options = {}) => {
    // Don't fade the message in if there is an 'X was typing'
    const $typingMessages = getTypingMessages(data);
    if ($typingMessages.length !== 0) {
--- a/examples/cluster-haproxy/server/package.json
+++ b/examples/cluster-haproxy/server/package.json
@@ -8,7 +8,7 @@
  "license": "BSD",
  "dependencies": {
    "express": "4.13.4",
-    "socket.io": "^3.1.0",
+    "socket.io": "^4.0.0",
    "socket.io-redis": "^6.0.1"
  },
  "scripts": {
--- a/examples/cluster-httpd/server/package.json
+++ b/examples/cluster-httpd/server/package.json
@@ -8,7 +8,7 @@
  "license": "BSD",
  "dependencies": {
    "express": "4.13.4",
-    "socket.io": "^3.1.0",
+    "socket.io": "^4.0.0",
    "socket.io-redis": "^6.0.1"
  },
  "scripts": {
--- a/examples/cluster-nginx/client/package.json
+++ b/examples/cluster-nginx/client/package.json
@@ -7,7 +7,7 @@
  "private": true,
  "license": "MIT",
  "dependencies": {
-    "socket.io-client": "^3.1.0"
+    "socket.io-client": "^4.0.0"
  },
  "scripts": {
    "start": "node index.js"
--- a/examples/cluster-nginx/server/package.json
+++ b/examples/cluster-nginx/server/package.json
@@ -8,7 +8,7 @@
  "license": "MIT",
  "dependencies": {
    "express": "4.13.4",
-    "socket.io": "^3.1.0",
+    "socket.io": "^4.0.0",
    "socket.io-redis": "^6.0.1"
  },
  "scripts": {
--- a/examples/cluster-traefik/server/package.json
+++ b/examples/cluster-traefik/server/package.json
@@ -8,7 +8,7 @@
  "license": "MIT",
  "dependencies": {
    "express": "4.13.4",
-    "socket.io": "^3.1.0",
+    "socket.io": "^4.0.0",
    "socket.io-redis": "^6.0.1"
  },
  "scripts": {
--- a/examples/create-react-app-example/package.json
+++ b/examples/create-react-app-example/package.json
@@ -9,8 +9,8 @@
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-scripts": "3.4.1",
-    "socket.io": "^2.3.0",
-    "socket.io-client": "^2.3.0"
+    "socket.io": "4",
+    "socket.io-client": "4"
  },
  "scripts": {
    "start": "react-scripts start",
--- a/examples/create-react-app-example/server.js
+++ b/examples/create-react-app-example/server.js
@@ -1,4 +1,8 @@
-const io = require('socket.io')();
+const io = require('socket.io')({
+  cors: {
+    origin: ['http://localhost:3000']
+  }
+});

 io.on('connection', socket => {
  console.log(`connect: ${socket.id}`);
--- a/examples/create-react-app-example/yarn.lock
+++ b/examples/create-react-app-example/yarn.lock
--- a/examples/custom-parsers/package.json
+++ b/examples/custom-parsers/package.json
@@ -12,10 +12,10 @@
    "component-emitter": "^1.2.1",
    "express": "^4.15.2",
    "schemapack": "^1.4.2",
-    "socket.io": "socketio/socket.io",
-    "socket.io-client": "socketio/socket.io-client",
-    "socket.io-json-parser": "^1.0.0",
-    "socket.io-msgpack-parser": "^1.0.0",
+    "socket.io": "^4.0.0",
+    "socket.io-client": "^4.0.0",
+    "socket.io-json-parser": "^3.0.0",
+    "socket.io-msgpack-parser": "^3.0.1",
    "webpack": "^2.4.1"
  }
 }
--- a/examples/custom-parsers/public/.gitignore
+++ b/examples/custom-parsers/public/.gitignore
@@ -0,0 +1 @@
+*.bundle.js
--- a/examples/custom-parsers/src/custom-parser.js
+++ b/examples/custom-parsers/src/custom-parser.js
@@ -40,12 +40,12 @@ const errorPacket = {
 };

 class Encoder {
-  encode (packet, callback) {
+  encode (packet) {
    switch (packet.type) {
      case TYPES.EVENT:
-        return callback([ this.pack(packet) ]);
+        return [ this.pack(packet) ];
      default:
-        return callback([ JSON.stringify(packet) ]);
+        return [ JSON.stringify(packet) ];
    }
  }
  pack (packet) {
--- a/examples/custom-parsers/src/server.js
+++ b/examples/custom-parsers/src/server.js
@@ -14,15 +14,22 @@ const msgpackParser = require('socket.io-msgpack-parser');
 const jsonParser = require('socket.io-json-parser');
 const customParser = require('./custom-parser');

-let server1 = io(3001, {});
+const cors = {
+  origin: ["http://localhost:3000"]
+}
+
+let server1 = io(3001, { cors });
 let server2 = io(3002, {
-  parser: msgpackParser
+  parser: msgpackParser,
+  cors
 });
 let server3 = io(3003, {
-  parser: jsonParser
+  parser: jsonParser,
+  cors
 });
 let server4 = io(3004, {
-  parser: customParser
+  parser: customParser,
+  cors
 });

 let string = [];
--- a/examples/es-modules/package-lock.json
+++ b/examples/es-modules/package-lock.json
@@ -1,217 +0,0 @@
-{
-  "name": "es-modules",
-  "version": "1.0.0",
-  "lockfileVersion": 1,
-  "requires": true,
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-        "socket.io-parser": "~4.0.1"
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-      "resolved": "https://registry.npmjs.org/vary/-/vary-1.1.2.tgz",
-      "integrity": "sha1-IpnwLG3tMNSllhsLn3RSShj2NPw="
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-      "integrity": "sha512-kyFwXuV/5ymf+IXhS6f0+eAFvydbaBW3zjpT6hUdAh/hbVjTIB5EHBGi0bPoCLSK2wcuz3BrEkB9LrYv1Nm4NQ=="
-    },
-    "xmlhttprequest-ssl": {
-      "version": "1.5.5",
-      "resolved": "https://registry.npmjs.org/xmlhttprequest-ssl/-/xmlhttprequest-ssl-1.5.5.tgz",
-      "integrity": "sha1-wodrBhaKrcQOV9l+gRkayPQ5iz4="
-    },
-    "yeast": {
-      "version": "0.1.2",
-      "resolved": "https://registry.npmjs.org/yeast/-/yeast-0.1.2.tgz",
-      "integrity": "sha1-AI4G2AlDIMNy28L47XagymyKxBk="
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-  }
-}
--- a/examples/es-modules/package.json
+++ b/examples/es-modules/package.json
@@ -9,7 +9,7 @@
    "node": ">=12.17.0"
  },
  "dependencies": {
-    "socket.io": "^3.0.0",
-    "socket.io-client": "^3.0.0"
+    "socket.io": "^4.0.0",
+    "socket.io-client": "^4.0.0"
  }
 }
--- a/examples/passport-example/index.js
+++ b/examples/passport-example/index.js
@@ -51,9 +51,9 @@ app.post(
 app.post("/logout", (req, res) => {
  console.log(`logout ${req.session.id}`);
  const socketId = req.session.socketId;
-  if (socketId && io.of("/").connected[socketId]) {
+  if (socketId && io.of("/").sockets.get(socketId)) {
    console.log(`forcefully closing socket ${socketId}`);
-    io.sockets.connected[socketId].disconnect(true);
+    io.of("/").sockets.get(socketId).disconnect(true);
  }
  req.logout();
  res.cookie("connect.sid", "", { expires: new Date() });
--- a/examples/passport-example/package-lock.json
+++ b/examples/passport-example/package-lock.json
@@ -1,783 +0,0 @@
-{
-  "name": "passport-example",
-  "version": "0.0.1",
-  "lockfileVersion": 1,
-  "requires": true,
-  "dependencies": {
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-      "requires": {
-        "mime-types": "~2.1.24",
-        "negotiator": "0.6.2"
-      }
-    },
-    "after": {
-      "version": "0.8.2",
-      "resolved": "https://registry.npmjs.org/after/-/after-0.8.2.tgz",
-      "integrity": "sha1-/ts5T58OAqqXaOcCvaI7UF+ufh8="
-    },
-    "array-flatten": {
-      "version": "1.1.1",
-      "resolved": "https://registry.npmjs.org/array-flatten/-/array-flatten-1.1.1.tgz",
-      "integrity": "sha1-ml9pkFGx5wczKPKgCJaLZOopVdI="
-    },
-    "arraybuffer.slice": {
-      "version": "0.0.7",
-      "resolved": "https://registry.npmjs.org/arraybuffer.slice/-/arraybuffer.slice-0.0.7.tgz",
-      "integrity": "sha512-wGUIVQXuehL5TCqQun8OW81jGzAWycqzFF8lFp+GOM5BXLYj3bKNsYC4daB7n6XjCqxQA/qgTJ+8ANR3acjrog=="
-    },
-    "async-limiter": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/async-limiter/-/async-limiter-1.0.1.tgz",
-      "integrity": "sha512-csOlWGAcRFJaI6m+F2WKdnMKr4HhdhFVBk0H/QbJFMCr+uO2kwohwXQPxw/9OCxp05r5ghVBFSyioixx3gfkNQ=="
-    },
-    "backo2": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/backo2/-/backo2-1.0.2.tgz",
-      "integrity": "sha1-MasayLEpNjRj41s+u2n038+6eUc="
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-      "resolved": "https://registry.npmjs.org/base64-arraybuffer/-/base64-arraybuffer-0.1.5.tgz",
-      "integrity": "sha1-c5JncZI7Whl0etZmqlzUv5xunOg="
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-      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/base64id/-/base64id-2.0.0.tgz",
-      "integrity": "sha512-lGe34o6EHj9y3Kts9R4ZYs/Gr+6N7MCaMlIFA3F1R2O5/m7K06AxfSeO5530PEERE6/WyEg3lsuyw4GHlPZHog=="
-    },
-    "better-assert": {
-      "version": "1.0.2",
-      "resolved": "https://registry.npmjs.org/better-assert/-/better-assert-1.0.2.tgz",
-      "integrity": "sha1-QIZrnhueC1W0gYlDEeaPr/rrxSI=",
-      "requires": {
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-      }
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-    "blob": {
-      "version": "0.0.5",
-      "resolved": "https://registry.npmjs.org/blob/-/blob-0.0.5.tgz",
-      "integrity": "sha512-gaqbzQPqOoamawKg0LGVd7SzLgXS+JH61oWprSLH+P+abTczqJbhTR8CmJ2u9/bUYNmHTGJx/UEmn6doAvvuig=="
-    },
-    "body-parser": {
-      "version": "1.19.0",
-      "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.19.0.tgz",
-      "integrity": "sha512-dhEPs72UPbDnAQJ9ZKMNTP6ptJaionhP5cBb541nXPlW60Jepo9RV/a4fX4XWW9CuFNK22krhrj1+rgzifNCsw==",
-      "requires": {
-        "bytes": "3.1.0",
-        "content-type": "~1.0.4",
-        "debug": "2.6.9",
-        "depd": "~1.1.2",
-        "http-errors": "1.7.2",
-        "iconv-lite": "0.4.24",
-        "on-finished": "~2.3.0",
-        "qs": "6.7.0",
-        "raw-body": "2.4.0",
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-      "resolved": "https://registry.npmjs.org/bytes/-/bytes-3.1.0.tgz",
-      "integrity": "sha512-zauLjrfCG+xvoyaqLoV8bLVXXNGC4JqlxFCutSDWA6fJrTo2ZuvLYTqZ7aHBLZSMOopbzwv8f+wZcVzfVTI2Dg=="
-    },
-    "callsite": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/callsite/-/callsite-1.0.0.tgz",
-      "integrity": "sha1-KAOY5dZkvXQDi28JBRU+borxvCA="
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-      "integrity": "sha1-AMYIq33Nk4l8AAllGx06jh5zu9E="
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--- a/examples/passport-example/package.json
+++ b/examples/passport-example/package.json
@@ -8,7 +8,7 @@
    "express-session": "~1.17.1",
    "passport": "~0.4.1",
    "passport-local": "~1.0.0",
-    "socket.io": "~2.3.0"
+    "socket.io": "^4.0.0"
  },
  "scripts": {
    "start": "node index.js"
--- a/examples/private-messaging/.gitignore
+++ b/examples/private-messaging/.gitignore
@@ -0,0 +1,24 @@
+.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?
+package-lock.json
--- a/examples/private-messaging/README.md
+++ b/examples/private-messaging/README.md
@@ -0,0 +1,23 @@
+# Private messaging with Socket.IO
+
+Please read the related guide:
+
+- [Part I](https://socket.io/get-started/private-messaging-part-1/): initial implementation
+- [Part II](https://socket.io/get-started/private-messaging-part-2/): persistent user ID
+- [Part III](https://socket.io/get-started/private-messaging-part-3/): persistent messages
+- [Part IV](https://socket.io/get-started/private-messaging-part-4/): scaling up
+
+## Running the frontend
+
+```
+npm install
+npm run serve
+```
+
+### Running the server
+
+```
+cd server
+npm install
+npm start
+```
--- a/examples/private-messaging/babel.config.js
+++ b/examples/private-messaging/babel.config.js
@@ -0,0 +1,5 @@
+module.exports = {
+  presets: [
+    '@vue/cli-plugin-babel/preset'
+  ]
+}
--- a/examples/private-messaging/package.json
+++ b/examples/private-messaging/package.json
@@ -0,0 +1,43 @@
+{
+  "name": "private-messaging",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "serve": "vue-cli-service serve",
+    "build": "vue-cli-service build",
+    "lint": "vue-cli-service lint"
+  },
+  "dependencies": {
+    "core-js": "^3.6.5",
+    "socket.io-client": "^4.0.0",
+    "vue": "^2.6.11"
+  },
+  "devDependencies": {
+    "@vue/cli-plugin-babel": "~4.5.0",
+    "@vue/cli-plugin-eslint": "~4.5.0",
+    "@vue/cli-service": "~4.5.0",
+    "babel-eslint": "^10.1.0",
+    "eslint": "^6.7.2",
+    "eslint-plugin-vue": "^6.2.2",
+    "vue-template-compiler": "^2.6.11"
+  },
+  "eslintConfig": {
+    "root": true,
+    "env": {
+      "node": true
+    },
+    "extends": [
+      "plugin:vue/essential",
+      "eslint:recommended"
+    ],
+    "parserOptions": {
+      "parser": "babel-eslint"
+    },
+    "rules": {}
+  },
+  "browserslist": [
+    "> 1%",
+    "last 2 versions",
+    "not dead"
+  ]
+}
--- a/examples/private-messaging/public/favicon.ico
+++ b/examples/private-messaging/public/favicon.ico
--- a/examples/private-messaging/public/fonts/Lato-Regular.ttf
+++ b/examples/private-messaging/public/fonts/Lato-Regular.ttf
--- a/examples/private-messaging/public/index.html
+++ b/examples/private-messaging/public/index.html
@@ -0,0 +1,17 @@
+<!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">
+    <title>Private messaging with Socket.IO</title>
+  </head>
+  <body>
+    <noscript>
+      <strong>We're sorry but this application 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>
--- a/examples/private-messaging/server/cluster.js
+++ b/examples/private-messaging/server/cluster.js
@@ -0,0 +1,31 @@
+const cluster = require("cluster");
+const http = require("http");
+const { setupMaster } = require("@socket.io/sticky");
+
+const WORKERS_COUNT = 4;
+
+if (cluster.isMaster) {
+  console.log(`Master ${process.pid} is running`);
+
+  for (let i = 0; i < WORKERS_COUNT; i++) {
+    cluster.fork();
+  }
+
+  cluster.on("exit", (worker) => {
+    console.log(`Worker ${worker.process.pid} died`);
+    cluster.fork();
+  });
+
+  const httpServer = http.createServer();
+  setupMaster(httpServer, {
+    loadBalancingMethod: "least-connection", // either "random", "round-robin" or "least-connection"
+  });
+  const PORT = process.env.PORT || 3000;
+
+  httpServer.listen(PORT, () =>
+    console.log(`server listening at http://localhost:${PORT}`)
+  );
+} else {
+  console.log(`Worker ${process.pid} started`);
+  require("./index");
+}
--- a/examples/private-messaging/server/docker-compose.yml
+++ b/examples/private-messaging/server/docker-compose.yml
@@ -0,0 +1,7 @@
+version: "3"
+
+services:
+  redis:
+    image: redis:5
+    ports:
+      - "6379:6379"
--- a/examples/private-messaging/server/index.js
+++ b/examples/private-messaging/server/index.js
@@ -0,0 +1,125 @@
+const httpServer = require("http").createServer();
+const Redis = require("ioredis");
+const redisClient = new Redis();
+const io = require("socket.io")(httpServer, {
+  cors: {
+    origin: "http://localhost:8080",
+  },
+  adapter: require("socket.io-redis")({
+    pubClient: redisClient,
+    subClient: redisClient.duplicate(),
+  }),
+});
+
+const { setupWorker } = require("@socket.io/sticky");
+const crypto = require("crypto");
+const randomId = () => crypto.randomBytes(8).toString("hex");
+
+const { RedisSessionStore } = require("./sessionStore");
+const sessionStore = new RedisSessionStore(redisClient);
+
+const { RedisMessageStore } = require("./messageStore");
+const messageStore = new RedisMessageStore(redisClient);
+
+io.use(async (socket, next) => {
+  const sessionID = socket.handshake.auth.sessionID;
+  if (sessionID) {
+    const session = await sessionStore.findSession(sessionID);
+    if (session) {
+      socket.sessionID = sessionID;
+      socket.userID = session.userID;
+      socket.username = session.username;
+      return next();
+    }
+  }
+  const username = socket.handshake.auth.username;
+  if (!username) {
+    return next(new Error("invalid username"));
+  }
+  socket.sessionID = randomId();
+  socket.userID = randomId();
+  socket.username = username;
+  next();
+});
+
+io.on("connection", async (socket) => {
+  // persist session
+  sessionStore.saveSession(socket.sessionID, {
+    userID: socket.userID,
+    username: socket.username,
+    connected: true,
+  });
+
+  // emit session details
+  socket.emit("session", {
+    sessionID: socket.sessionID,
+    userID: socket.userID,
+  });
+
+  // join the "userID" room
+  socket.join(socket.userID);
+
+  // fetch existing users
+  const users = [];
+  const [messages, sessions] = await Promise.all([
+    messageStore.findMessagesForUser(socket.userID),
+    sessionStore.findAllSessions(),
+  ]);
+  const messagesPerUser = new Map();
+  messages.forEach((message) => {
+    const { from, to } = message;
+    const otherUser = socket.userID === from ? to : from;
+    if (messagesPerUser.has(otherUser)) {
+      messagesPerUser.get(otherUser).push(message);
+    } else {
+      messagesPerUser.set(otherUser, [message]);
+    }
+  });
+
+  sessions.forEach((session) => {
+    users.push({
+      userID: session.userID,
+      username: session.username,
+      connected: session.connected,
+      messages: messagesPerUser.get(session.userID) || [],
+    });
+  });
+  socket.emit("users", users);
+
+  // notify existing users
+  socket.broadcast.emit("user connected", {
+    userID: socket.userID,
+    username: socket.username,
+    connected: true,
+    messages: [],
+  });
+
+  // forward the private message to the right recipient (and to other tabs of the sender)
+  socket.on("private message", ({ content, to }) => {
+    const message = {
+      content,
+      from: socket.userID,
+      to,
+    };
+    socket.to(to).to(socket.userID).emit("private message", message);
+    messageStore.saveMessage(message);
+  });
+
+  // notify users upon disconnection
+  socket.on("disconnect", async () => {
+    const matchingSockets = await io.in(socket.userID).allSockets();
+    const isDisconnected = matchingSockets.size === 0;
+    if (isDisconnected) {
+      // notify other users
+      socket.broadcast.emit("user disconnected", socket.userID);
+      // update the connection status of the session
+      sessionStore.saveSession(socket.sessionID, {
+        userID: socket.userID,
+        username: socket.username,
+        connected: false,
+      });
+    }
+  });
+});
+
+setupWorker(io);
--- a/examples/private-messaging/server/messageStore.js
+++ b/examples/private-messaging/server/messageStore.js
@@ -0,0 +1,54 @@
+/* abstract */ class MessageStore {
+  saveMessage(message) {}
+  findMessagesForUser(userID) {}
+}
+
+class InMemoryMessageStore extends MessageStore {
+  constructor() {
+    super();
+    this.messages = [];
+  }
+
+  saveMessage(message) {
+    this.messages.push(message);
+  }
+
+  findMessagesForUser(userID) {
+    return this.messages.filter(
+      ({ from, to }) => from === userID || to === userID
+    );
+  }
+}
+
+const CONVERSATION_TTL = 24 * 60 * 60;
+
+class RedisMessageStore extends MessageStore {
+  constructor(redisClient) {
+    super();
+    this.redisClient = redisClient;
+  }
+
+  saveMessage(message) {
+    const value = JSON.stringify(message);
+    this.redisClient
+      .multi()
+      .rpush(`messages:${message.from}`, value)
+      .rpush(`messages:${message.to}`, value)
+      .expire(`messages:${message.from}`, CONVERSATION_TTL)
+      .expire(`messages:${message.to}`, CONVERSATION_TTL)
+      .exec();
+  }
+
+  findMessagesForUser(userID) {
+    return this.redisClient
+      .lrange(`messages:${userID}`, 0, -1)
+      .then((results) => {
+        return results.map((result) => JSON.parse(result));
+      });
+  }
+}
+
+module.exports = {
+  InMemoryMessageStore,
+  RedisMessageStore,
+};
--- a/examples/private-messaging/server/package.json
+++ b/examples/private-messaging/server/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "server",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "start": "node cluster.js"
+  },
+  "author": "Damien Arrachequesne <damien.arrachequesne@gmail.com>",
+  "license": "MIT",
+  "dependencies": {
+    "@socket.io/sticky": "^1.0.0",
+    "ioredis": "^4.22.0",
+    "socket.io": "^4.0.0",
+    "socket.io-redis": "^6.0.1"
+  }
+}
--- a/examples/private-messaging/server/sessionStore.js
+++ b/examples/private-messaging/server/sessionStore.js
@@ -0,0 +1,89 @@
+/* abstract */ class SessionStore {
+  findSession(id) {}
+  saveSession(id, session) {}
+  findAllSessions() {}
+}
+
+class InMemorySessionStore extends SessionStore {
+  constructor() {
+    super();
+    this.sessions = new Map();
+  }
+
+  findSession(id) {
+    return this.sessions.get(id);
+  }
+
+  saveSession(id, session) {
+    this.sessions.set(id, session);
+  }
+
+  findAllSessions() {
+    return [...this.sessions.values()];
+  }
+}
+
+const SESSION_TTL = 24 * 60 * 60;
+const mapSession = ([userID, username, connected]) =>
+  userID ? { userID, username, connected: connected === "true" } : undefined;
+
+class RedisSessionStore extends SessionStore {
+  constructor(redisClient) {
+    super();
+    this.redisClient = redisClient;
+  }
+
+  findSession(id) {
+    return this.redisClient
+      .hmget(`session:${id}`, "userID", "username", "connected")
+      .then(mapSession);
+  }
+
+  saveSession(id, { userID, username, connected }) {
+    this.redisClient
+      .multi()
+      .hset(
+        `session:${id}`,
+        "userID",
+        userID,
+        "username",
+        username,
+        "connected",
+        connected
+      )
+      .expire(`session:${id}`, SESSION_TTL)
+      .exec();
+  }
+
+  async findAllSessions() {
+    const keys = new Set();
+    let nextIndex = 0;
+    do {
+      const [nextIndexAsStr, results] = await this.redisClient.scan(
+        nextIndex,
+        "MATCH",
+        "session:*",
+        "COUNT",
+        "100"
+      );
+      nextIndex = parseInt(nextIndexAsStr, 10);
+      results.forEach((s) => keys.add(s));
+    } while (nextIndex !== 0);
+    const commands = [];
+    keys.forEach((key) => {
+      commands.push(["hmget", key, "userID", "username", "connected"]);
+    });
+    return this.redisClient
+      .multi(commands)
+      .exec()
+      .then((results) => {
+        return results
+          .map(([err, session]) => (err ? undefined : mapSession(session)))
+          .filter((v) => !!v);
+      });
+  }
+}
+module.exports = {
+  InMemorySessionStore,
+  RedisSessionStore,
+};
--- a/examples/private-messaging/src/App.vue
+++ b/examples/private-messaging/src/App.vue
@@ -0,0 +1,78 @@
+<template>
+  <div id="app">
+    <select-username
+      v-if="!usernameAlreadySelected"
+      @input="onUsernameSelection"
+    />
+    <chat v-else />
+  </div>
+</template>
+
+<script>
+import SelectUsername from "./components/SelectUsername";
+import Chat from "./components/Chat";
+import socket from "./socket";
+
+export default {
+  name: "App",
+  components: {
+    Chat,
+    SelectUsername,
+  },
+  data() {
+    return {
+      usernameAlreadySelected: false,
+    };
+  },
+  methods: {
+    onUsernameSelection(username) {
+      this.usernameAlreadySelected = true;
+      socket.auth = { username };
+      socket.connect();
+    },
+  },
+  created() {
+    const sessionID = localStorage.getItem("sessionID");
+
+    if (sessionID) {
+      this.usernameAlreadySelected = true;
+      socket.auth = { sessionID };
+      socket.connect();
+    }
+
+    socket.on("session", ({ sessionID, userID }) => {
+      // attach the session ID to the next reconnection attempts
+      socket.auth = { sessionID };
+      // store it in the localStorage
+      localStorage.setItem("sessionID", sessionID);
+      // save the ID of the user
+      socket.userID = userID;
+    });
+
+    socket.on("connect_error", (err) => {
+      if (err.message === "invalid username") {
+        this.usernameAlreadySelected = false;
+      }
+    });
+  },
+  destroyed() {
+    socket.off("connect_error");
+  },
+};
+</script>
+
+<style>
+body {
+  margin: 0;
+}
+
+@font-face {
+  font-family: Lato;
+  src: url("/fonts/Lato-Regular.ttf");
+}
+
+#app {
+  font-family: Lato, Arial, sans-serif;
+  font-size: 14px;
+}
+</style>
--- a/examples/private-messaging/src/components/Chat.vue
+++ b/examples/private-messaging/src/components/Chat.vue
@@ -0,0 +1,165 @@
+<template>
+  <div>
+    <div class="left-panel">
+      <user
+        v-for="user in users"
+        :key="user.userID"
+        :user="user"
+        :selected="selectedUser === user"
+        @select="onSelectUser(user)"
+      />
+    </div>
+    <message-panel
+      v-if="selectedUser"
+      :user="selectedUser"
+      @input="onMessage"
+      class="right-panel"
+    />
+  </div>
+</template>
+
+<script>
+import socket from "../socket";
+import User from "./User";
+import MessagePanel from "./MessagePanel";
+
+export default {
+  name: "Chat",
+  components: { User, MessagePanel },
+  data() {
+    return {
+      selectedUser: null,
+      users: [],
+    };
+  },
+  methods: {
+    onMessage(content) {
+      if (this.selectedUser) {
+        socket.emit("private message", {
+          content,
+          to: this.selectedUser.userID,
+        });
+        this.selectedUser.messages.push({
+          content,
+          fromSelf: true,
+        });
+      }
+    },
+    onSelectUser(user) {
+      this.selectedUser = user;
+      user.hasNewMessages = false;
+    },
+  },
+  created() {
+    socket.on("connect", () => {
+      this.users.forEach((user) => {
+        if (user.self) {
+          user.connected = true;
+        }
+      });
+    });
+
+    socket.on("disconnect", () => {
+      this.users.forEach((user) => {
+        if (user.self) {
+          user.connected = false;
+        }
+      });
+    });
+
+    const initReactiveProperties = (user) => {
+      user.hasNewMessages = false;
+    };
+
+    socket.on("users", (users) => {
+      users.forEach((user) => {
+        user.messages.forEach((message) => {
+          message.fromSelf = message.from === socket.userID;
+        });
+        for (let i = 0; i < this.users.length; i++) {
+          const existingUser = this.users[i];
+          if (existingUser.userID === user.userID) {
+            existingUser.connected = user.connected;
+            existingUser.messages = user.messages;
+            return;
+          }
+        }
+        user.self = user.userID === socket.userID;
+        initReactiveProperties(user);
+        this.users.push(user);
+      });
+      // put the current user first, and sort by username
+      this.users.sort((a, b) => {
+        if (a.self) return -1;
+        if (b.self) return 1;
+        if (a.username < b.username) return -1;
+        return a.username > b.username ? 1 : 0;
+      });
+    });
+
+    socket.on("user connected", (user) => {
+      for (let i = 0; i < this.users.length; i++) {
+        const existingUser = this.users[i];
+        if (existingUser.userID === user.userID) {
+          existingUser.connected = true;
+          return;
+        }
+      }
+      initReactiveProperties(user);
+      this.users.push(user);
+    });
+
+    socket.on("user disconnected", (id) => {
+      for (let i = 0; i < this.users.length; i++) {
+        const user = this.users[i];
+        if (user.userID === id) {
+          user.connected = false;
+          break;
+        }
+      }
+    });
+
+    socket.on("private message", ({ content, from, to }) => {
+      for (let i = 0; i < this.users.length; i++) {
+        const user = this.users[i];
+        const fromSelf = socket.userID === from;
+        if (user.userID === (fromSelf ? to : from)) {
+          user.messages.push({
+            content,
+            fromSelf,
+          });
+          if (user !== this.selectedUser) {
+            user.hasNewMessages = true;
+          }
+          break;
+        }
+      }
+    });
+  },
+  destroyed() {
+    socket.off("connect");
+    socket.off("disconnect");
+    socket.off("users");
+    socket.off("user connected");
+    socket.off("user disconnected");
+    socket.off("private message");
+  },
+};
+</script>
+
+<style scoped>
+.left-panel {
+  position: fixed;
+  left: 0;
+  top: 0;
+  bottom: 0;
+  width: 260px;
+  overflow-x: hidden;
+  background-color: #3f0e40;
+  color: white;
+}
+
+.right-panel {
+  margin-left: 260px;
+}
+</style>
--- a/examples/private-messaging/src/components/MessagePanel.vue
+++ b/examples/private-messaging/src/components/MessagePanel.vue
@@ -0,0 +1,101 @@
+<template>
+  <div>
+    <div class="header">
+      <status-icon :connected="user.connected" />{{ user.username }}
+    </div>
+
+    <ul class="messages">
+      <li
+        v-for="(message, index) in user.messages"
+        :key="index"
+        class="message"
+      >
+        <div v-if="displaySender(message, index)" class="sender">
+          {{ message.fromSelf ? "(yourself)" : user.username }}
+        </div>
+        {{ message.content }}
+      </li>
+    </ul>
+
+    <form @submit.prevent="onSubmit" class="form">
+      <textarea v-model="input" placeholder="Your message..." class="input" />
+      <button :disabled="!isValid" class="send-button">Send</button>
+    </form>
+  </div>
+</template>
+
+<script>
+import StatusIcon from "./StatusIcon";
+
+export default {
+  name: "MessagePanel",
+  components: {
+    StatusIcon,
+  },
+  props: {
+    user: Object,
+  },
+  data() {
+    return {
+      input: "",
+    };
+  },
+  methods: {
+    onSubmit() {
+      this.$emit("input", this.input);
+      this.input = "";
+    },
+    displaySender(message, index) {
+      return (
+        index === 0 ||
+        this.user.messages[index - 1].fromSelf !==
+          this.user.messages[index].fromSelf
+      );
+    },
+  },
+  computed: {
+    isValid() {
+      return this.input.length > 0;
+    },
+  },
+};
+</script>
+
+<style scoped>
+.header {
+  line-height: 40px;
+  padding: 10px 20px;
+  border-bottom: 1px solid #dddddd;
+}
+
+.messages {
+  margin: 0;
+  padding: 20px;
+}
+
+.message {
+  list-style: none;
+}
+
+.sender {
+  font-weight: bold;
+  margin-top: 5px;
+}
+
+.form {
+  padding: 10px;
+}
+
+.input {
+  width: 80%;
+  resize: none;
+  padding: 10px;
+  line-height: 1.5;
+  border-radius: 5px;
+  border: 1px solid #000;
+}
+
+.send-button {
+  vertical-align: top;
+}
+</style>
--- a/examples/private-messaging/src/components/SelectUsername.vue
+++ b/examples/private-messaging/src/components/SelectUsername.vue
@@ -0,0 +1,36 @@
+<template>
+  <div class="select-username">
+    <form @submit.prevent="onSubmit">
+      <input v-model="username" placeholder="Your username..." />
+      <button :disabled="!isValid">Send</button>
+    </form>
+  </div>
+</template>
+
+<script>
+export default {
+  name: "SelectUsername",
+  data() {
+    return {
+      username: "",
+    };
+  },
+  computed: {
+    isValid() {
+      return this.username.length > 2;
+    },
+  },
+  methods: {
+    onSubmit() {
+      this.$emit("input", this.username);
+    },
+  },
+};
+</script>
+
+<style scoped>
+.select-username {
+  width: 300px;
+  margin: 200px auto 0;
+}
+</style>
--- a/examples/private-messaging/src/components/StatusIcon.vue
+++ b/examples/private-messaging/src/components/StatusIcon.vue
@@ -0,0 +1,27 @@
+<template>
+  <i class="icon" :class="{ connected: connected }"></i>
+</template>
+
+<script>
+export default {
+  name: "StatusIcon",
+  props: {
+    connected: Boolean,
+  },
+};
+</script>
+
+<style scoped>
+.icon {
+  height: 8px;
+  width: 8px;
+  border-radius: 50%;
+  display: inline-block;
+  background-color: #e38968;
+  margin-right: 6px;
+}
+
+.icon.connected {
+  background-color: #86bb71;
+}
+</style>
--- a/examples/private-messaging/src/components/User.vue
+++ b/examples/private-messaging/src/components/User.vue
@@ -0,0 +1,63 @@
+<template>
+  <div class="user" @click="onClick" :class="{ selected: selected }">
+    <div class="description">
+      <div class="name">
+        {{ user.username }} {{ user.self ? " (yourself)" : "" }}
+      </div>
+      <div class="status">
+        <status-icon :connected="user.connected" />{{ status }}
+      </div>
+    </div>
+    <div v-if="user.hasNewMessages" class="new-messages">!</div>
+  </div>
+</template>
+
+<script>
+import StatusIcon from "./StatusIcon";
+export default {
+  name: "User",
+  components: { StatusIcon },
+  props: {
+    user: Object,
+    selected: Boolean,
+  },
+  methods: {
+    onClick() {
+      this.$emit("select");
+    },
+  },
+  computed: {
+    status() {
+      return this.user.connected ? "online" : "offline";
+    },
+  },
+};
+</script>
+
+<style scoped>
+.selected {
+  background-color: #1164a3;
+}
+
+.user {
+  padding: 10px;
+}
+
+.description {
+  display: inline-block;
+}
+
+.status {
+  color: #92959e;
+}
+
+.new-messages {
+  color: white;
+  background-color: red;
+  width: 20px;
+  border-radius: 5px;
+  text-align: center;
+  float: right;
+  margin-top: 10px;
+}
+</style>
--- a/examples/private-messaging/src/main.js
+++ b/examples/private-messaging/src/main.js
@@ -0,0 +1,8 @@
+import Vue from "vue";
+import App from "./App.vue";
+
+Vue.config.productionTip = false;
+
+new Vue({
+  render: (h) => h(App),
+}).$mount("#app");
--- a/examples/private-messaging/src/socket.js
+++ b/examples/private-messaging/src/socket.js
@@ -0,0 +1,10 @@
+import { io } from "socket.io-client";
+
+const URL = "http://localhost:3000";
+const socket = io(URL, { autoConnect: false });
+
+socket.onAny((event, ...args) => {
+  console.log(event, args);
+});
+
+export default socket;
--- a/examples/react-native/package-lock.json
+++ b/examples/react-native/package-lock.json
--- a/examples/react-native/package.json
+++ b/examples/react-native/package.json
@@ -13,8 +13,8 @@
    "react-dom": "~16.9.0",
    "react-native": "https://github.com/expo/react-native/archive/sdk-37.0.1.tar.gz",
    "react-native-web": "~0.11.7",
-    "socket.io": "^3.0.1",
-    "socket.io-client": "^3.0.1"
+    "socket.io": "^4.0.0",
+    "socket.io-client": "^4.0.0"
  },
  "devDependencies": {
    "babel-preset-expo": "~8.1.0",
--- a/examples/tweet-stream/index.js
+++ b/examples/tweet-stream/index.js
@@ -7,7 +7,11 @@ const twitter = new Twitter({
  token_secret: process.env.TWITTER_TOKEN_SECRET
 });

-const io = require('socket.io')(process.env.PORT || 3000);
+const io = require('socket.io')(process.env.PORT || 3000, {
+  cors: {
+    origin: true
+  }
+});

 twitter.track('socket.io');
 twitter.track('javascript');
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Damien Arrachequesne	ccc5ec39a8	chore(release): 4.3.1 Diff: https://github.com/socketio/socket.io/compare/4.3.0...4.3.1	2021-10-17 00:02:16 +02:00
Josh Field	0ef2a4d02c	fix: fix server attachment (#4127 ) The check excluded an HTTPS server from being properly attached. Related: https://github.com/socketio/socket.io/issues/4124	2021-10-16 23:58:55 +02:00
Damien Arrachequesne	95810aa62d	chore(release): 4.3.0 Diff: https://github.com/socketio/socket.io/compare/4.2.0...4.3.0	2021-10-14 14:59:13 +02:00
Damien Arrachequesne	60edecb3bd	feat: serve ESM bundle Related: - `0661564dc2` - https://github.com/socketio/socket.io-client/issues/1198	2021-10-13 18:17:12 +02:00
Damien Arrachequesne	eb5fdbd03e	chore: bump engine.io to version 6.0.0 Release notes: https://github.com/socketio/engine.io/releases/tag/6.0.0 Diff: https://github.com/socketio/engine.io/compare/5.2.0...6.0.0	2021-10-12 00:05:10 +02:00
roh-kan	4974e9077c	docs: update .NET client library link (#4115 )	2021-10-08 14:18:03 +02:00
douira	033c5d399a	fix(typings): add name field to cookie option (#4099 ) Reference: `18a6eb89fb/lib/server.js (L355)`	2021-09-20 09:13:38 +02:00
Damien Arrachequesne	7a74b66872	test: remove hardcoded ports Related: https://github.com/socketio/socket.io/issues/3447	2021-09-09 08:57:11 +02:00
Damien Arrachequesne	dc81fcf461	fix: send volatile packets with binary attachments The binary attachments of volatile packets were discarded (only the header packet was sent) due to a bug introduced by [1]. Related: https://github.com/socketio/socket.io/issues/3919 [1]: `dc381b72c6`	2021-09-09 08:55:51 +02:00
Damien Arrachequesne	c100b7b61c	chore(release): 4.2.0 Diff: https://github.com/socketio/socket.io/compare/4.1.3...4.2.0	2021-08-30 09:21:00 +02:00
Damien Arrachequesne	f03eeca39a	chore: bump dependencies	2021-08-30 08:27:46 +02:00
Damien Arrachequesne	d8cc8aef7e	docs: update the link of the Repl.it badge The link will now point towards a sample project, instead of the root repository. Related: https://github.com/socketio/socket.io/issues/3934	2021-08-30 08:03:55 +02:00
Damien Arrachequesne	ccfd8caba6	fix(typings): allow async listener in typed events So that: ```ts socket.on("my-event", async () => { // ... }); ``` is valid under the @typescript-eslint/no-misused-promises rule. Related: https://github.com/socketio/socket.io-client/issues/1486	2021-08-30 08:01:29 +02:00
Tim Düsterhus	24fee27ba3	feat: ignore the query string when serving client JavaScript (#4024 ) Related: https://github.com/socketio/socket.io/issues/4023	2021-08-30 07:59:47 +02:00
brownman	310f8557a7	docs(examples): add missing module (#4018 ) Fixes the following error: > test/todo-management/todo.tests.ts:275:3 - error TS2582: Cannot find name 'describe'. Do you need to install type definitions for a test runner? Try `npm i --save-dev @types/jest` or `npm i --save-dev @types/mocha`. Co-authored-by: brownman <brownman@users.noreply.github.com>	2021-07-15 21:48:20 +02:00
Damien Arrachequesne	dbd2a07cda	chore(release): 4.1.3 Diff: https://github.com/socketio/socket.io/compare/4.1.2...4.1.3	2021-07-10 12:13:15 +02:00
Damien Arrachequesne	94e27cd072	fix: fix io.except() method Previously, calling `io.except("theroom").emit(...)` did not exclude the sockets in the given room. This method was forgotten in [1]. [1]: `ac9e8ca6c7`	2021-07-10 11:48:46 +02:00
Damien Arrachequesne	a4dffc6527	fix: remove x-sourcemap header This header is useless, as the client bundle already contains a sourceMappingURL field. Besides, Firefox prints the following warning: > <url> is being assigned a //# sourceMappingURL, but already has one Related: https://github.com/socketio/socket.io/issues/3958	2021-07-04 00:51:41 +02:00
Damien Arrachequesne	7c44893d78	chore: bump dependencies	2021-07-04 00:37:35 +02:00
Daniele TDC	b833f918c8	ci: update to node 16 (#3990 ) See also: https://github.com/nodejs/Release#release-schedule	2021-06-28 09:09:44 +02:00
Daniele TDC	24d8d1f67f	ci: update setup-node step (#3986 )	2021-06-24 14:53:46 +02:00
Damien Arrachequesne	6f2a50b932	docs(examples): update example to webpack 5	2021-06-15 22:35:06 +02:00
Damien Arrachequesne	1633150b2b	chore(release): 4.1.2 Diff: https://github.com/socketio/socket.io/compare/4.1.1...4.1.2	2021-05-17 23:17:31 +02:00
Damien Arrachequesne	0cb6ac95b4	fix(typings): ensure compatibility with TypeScript 3.x Labeled tuple elements were added in TypeScript 4.0. Reference: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-4-0.html#labeled-tuple-elements Related: https://github.com/socketio/socket.io/issues/3916	2021-05-17 23:15:22 +02:00
Damien Arrachequesne	a2cf2486c3	fix: ensure compatibility with previous versions of the adapter Using `socket.io@4.1.0` with `socket.io-adapter@2.2.0` would lead to the following error: > Uncaught Error: unknown packet type NaN Because the packet would be encoded twice, resulting in "undefined". See also: - `5579d40c24` - `dc381b72c6` Related: - https://github.com/socketio/socket.io/issues/3922 - https://github.com/socketio/socket.io/issues/3927	2021-05-17 23:14:36 +02:00
Damien Arrachequesne	995f38f4cc	chore(release): 4.1.1 Diff: https://github.com/socketio/socket.io/compare/4.1.0...4.1.1	2021-05-12 00:04:52 +02:00
Damien Arrachequesne	891b1870e9	fix(typings): properly type the adapter attribute Related: https://github.com/socketio/socket.io/issues/3796	2021-05-11 23:59:44 +02:00
Damien Arrachequesne	b84ed1e41c	fix(typings): properly type server-side events See also: `93cce05fb3`	2021-05-11 23:59:18 +02:00
Damien Arrachequesne	fb6b0efec9	chore(release): 4.1.0 Diff: https://github.com/socketio/socket.io/compare/4.0.2...4.1.0	2021-05-11 09:27:52 +02:00
Damien Arrachequesne	95d9e4a42f	test: fix randomly failing test	2021-05-11 00:06:03 +02:00
Damien Arrachequesne	499c89250d	feat: notify upon namespace creation A "new_namespace" event will be emitted when a new namespace is created: ```js io.on("new_namespace", (namespace) => { // ... }); ``` This could be used for example for registering the same middleware for each namespace. See https://github.com/socketio/socket.io/issues/3851	2021-05-11 00:09:18 +02:00
Damien Arrachequesne	93cce05fb3	feat: add support for inter-server communication Syntax: ```js // server A io.serverSideEmit("hello", "world"); // server B io.on("hello", (arg) => { console.log(arg); // prints "world" }); ``` With acknowledgements: ```js // server A io.serverSideEmit("hello", "world", (err, responses) => { console.log(responses); // prints ["hi"] }); // server B io.on("hello", (arg, callback) => { callback("hi"); }); ``` This feature replaces the customHook/customRequest API from the Redis adapter: https://github.com/socketio/socket.io-redis/issues/370	2021-05-11 00:07:20 +02:00
Damien Arrachequesne	dc381b72c6	perf: add support for the "wsPreEncoded" writing option Packets that are sent to multiple clients will now be pre-encoded for the WebSocket transport (which means simply prepending "4" - which is the "message" packet type in Engine.IO). Note: buffers are not pre-encoded, since they are sent without modification over the WebSocket connection See also: `7706b123df` engine.io diff: https://github.com/socketio/engine.io/compare/5.0.0...5.1.0	2021-05-11 00:06:03 +02:00
Damien Arrachequesne	9fff03487c	chore(release): 4.0.2 Diff: https://github.com/socketio/socket.io/compare/4.0.1...4.0.2	2021-05-06 14:38:26 +02:00
Damien Arrachequesne	b81ce4c9d0	fix(typings): make "engine" attribute public	2021-05-06 14:36:25 +02:00
Damien Arrachequesne	d65b6ee84c	fix: properly export the Socket class Before this change, `require("socket.io").Socket` would return "undefined". Note: having access to the Socket class allows users to modify its prototype. Related: https://github.com/socketio/socket.io/issues/3726	2021-05-06 14:36:12 +02:00
Damien Arrachequesne	3665aada47	docs(examples): basic CRUD application See also: https://socket.io/get-started/basic-crud-application/	2021-04-23 00:08:18 +02:00
Damien Arrachequesne	1faa7e3aea	chore(release): 4.0.1 Diff: https://github.com/socketio/socket.io/compare/4.0.0...4.0.1	2021-04-01 01:25:56 +02:00
Maxime Kjaer	a11152f42b	fix(typings): add fallback to untyped event listener (#3834 ) Related: https://github.com/socketio/socket.io/issues/3833	2021-03-31 11:37:37 +02:00
Maxime Kjaer	259f29720b	docs(examples): remove unnecessary type annotations (#3855 ) Typed events in Socket.IO 4.0 remove the need for writing type annotations in callbacks of reserved events.	2021-03-24 23:12:22 +01:00
Damien Arrachequesne	b4ae8d2e19	docs(examples): update all examples to Socket.IO v4	2021-03-18 15:07:04 +01:00
Adán Toscano	64be1c9985	docs(examples): fix chat example (#3787 )	2021-03-18 14:06:13 +01:00
Solomon English	1a72ae4fe2	fix(typings): update return type from emit (#3843 ) ``` (channel ? io.to(channel) : io).emit("stuff", message); ``` would no longer compile. Related: https://github.com/socketio/socket.io/issues/3844	2021-03-18 11:36:34 +01:00
Damien Arrachequesne	5eaeffc8e2	chore(release): 4.0.0 Diff: https://github.com/socketio/socket.io/compare/3.1.2...4.0.0	2021-03-10 12:43:53 +01:00
Damien Arrachequesne	1b6d6de4ed	chore: include Engine.IO v5 Release notes: https://github.com/socketio/engine.io/releases/tag/5.0.0	2021-03-10 11:14:33 +01:00
Maxime Kjaer	0107510ba8	feat: add support for typed events (#3822 ) Syntax: ```ts interface ClientToServerEvents { "my-event": (a: number, b: string, c: number[]) => void; } interface ServerToClientEvents { hello: (message: string) => void; } const io = new Server<ClientToServerEvents, ServerToClientEvents>(httpServer); io.emit("hello", "world"); io.on("connection", (socket) => { socket.on("my-event", (a, b, c) => { // ... }); socket.emit("hello", "again"); }); ``` The events are not typed by default (inferred as any), so this change is backward compatible. Note: we could also have reused the method here ([1]) to add types to the EventEmitter, instead of creating a StrictEventEmitter class. Related: https://github.com/socketio/socket.io/issues/3742 [1]: https://github.com/binier/tiny-typed-emitter	2021-03-10 00:18:13 +01:00
Damien Arrachequesne	b25495c069	feat: add some utility methods This commit adds the following methods: - fetchSockets: returns the matching socket instances Syntax: ```js // return all Socket instances const sockets = await io.fetchSockets(); // return all Socket instances of the "admin" namespace in the "room1" room const sockets = await io.of("/admin").in("room1").fetchSockets(); ``` - socketsJoin: makes the matching socket instances join the specified rooms Syntax: ```js // make all Socket instances join the "room1" room io.socketsJoin("room1"); // make all Socket instances of the "admin" namespace in the "room1" room join the "room2" room io.of("/admin").in("room1").socketsJoin("room2"); ``` - socketsLeave: makes the matching socket instances leave the specified rooms Syntax: ```js // make all Socket instances leave the "room1" room io.socketsLeave("room1"); // make all Socket instances of the "admin" namespace in the "room1" room leave the "room2" room io.of("/admin").in("room1").socketsLeave("room2"); ``` - disconnectSockets: makes the matching socket instances disconnect Syntax: ```js // make all Socket instances disconnect io.disconnectSockets(); // make all Socket instances of the "admin" namespace in the "room1" room disconnect io.of("/admin").in("room1").disconnectSockets(); ``` Those methods share the same semantics as broadcasting. They will also work with multiple Socket.IO servers when using the Redis adapter. In that case, the fetchSockets() method will return a list of RemoteSocket instances, which expose a subset of the methods and attributes of the Socket class (the "request" attribute cannot be mocked, for example). Related: - https://github.com/socketio/socket.io/issues/3042 - https://github.com/socketio/socket.io/issues/3418 - https://github.com/socketio/socket.io/issues/3570 - https://github.com/socketio/socket.io-redis/issues/283	2021-03-02 11:17:21 +01:00
Damien Arrachequesne	085d1de9df	feat: allow to pass an array to io.to(...) In some cases it is necessary to pass an array of rooms instead of a single room. New syntax: ``` io.to(["room1", "room2"]).except(["room3"]).emit(...); socket.to(["room1", "room2"]).except(["room3"]).emit(...); ``` Related: https://github.com/socketio/socket.io/issues/3048	2021-03-01 23:20:46 +01:00
Damien Arrachequesne	ac9e8ca6c7	fix: make io.to(...) immutable Previously, broadcasting to a given room (by calling `io.to()`) would mutate the io instance, which could lead to surprising behaviors, like: ```js io.to("room1"); io.to("room2").emit(...); // also sent to room1 // or with async/await io.to("room3").emit("details", await fetchDetails()); // random behavior: maybe in room3, maybe to all clients ``` Calling `io.to()` (or any other broadcast modifier) will now return an immutable instance. Related: - https://github.com/socketio/socket.io/issues/3431 - https://github.com/socketio/socket.io/issues/3444	2021-03-01 23:17:08 +01:00
Sebastiaan Marynissen	7de2e87e88	feat: allow to exclude specific rooms when broadcasting (#3789 ) New syntax: ``` io.except("room1").emit(...); io.to("room1").except("room2").emit(...); socket.broadcast.except("room1").emit(...); socket.to("room1").except("room2").emit(...); ``` Related: - https://github.com/socketio/socket.io/issues/3629 - https://github.com/socketio/socket.io/issues/3657	2021-03-01 09:30:58 +01:00
Damien Arrachequesne	225ade062a	chore(release): 3.1.2 Diff: https://github.com/socketio/socket.io/compare/3.1.1...3.1.2	2021-02-26 01:18:42 +01:00
Damien Arrachequesne	494c64e44f	fix: ignore packet received after disconnection Related: https://github.com/socketio/socket.io/issues/3095	2021-02-26 00:58:30 +01:00
Damien Arrachequesne	67a61e39e6	chore: loosen the version requirement of @types/node Related: https://github.com/socketio/socket.io/issues/3793	2021-02-26 00:58:01 +01:00
Damien Arrachequesne	7467216e02	docs(examples): 4th and final part of the "private messaging" example See also: https://socket.io/get-started/private-messaging-part-4/	2021-02-17 00:24:23 +01:00
Damien Arrachequesne	7247b4051f	docs(examples): 3rd part of the "private messaging" example See also: https://socket.io/get-started/private-messaging-part-3/	2021-02-17 00:22:55 +01:00
Damien Arrachequesne	992c9380c3	docs(examples): 2nd part of the "private messaging" example See also: https://socket.io/get-started/private-messaging-part-2/	2021-02-15 01:09:12 +01:00
Damien Arrachequesne	8b404f424b	docs(examples): 1st part of the "private messaging" example	2021-02-10 00:33:39 +01:00