import { Server } from "socket.io"; const io = new Server(8080, { cors: { origin: "http://localhost:4200", methods: ["GET", "POST"] } }); interface Todo { completed: boolean; editing: boolean; title: string; } let todos: Array = []; io.on("connection", (socket) => { socket.emit("todos", todos); // note: we could also create a CRUD (create/read/update/delete) service for the todo list socket.on("update-store", (updatedTodos) => { // store it locally todos = updatedTodos; // broadcast to everyone but the sender socket.broadcast.emit("todos", todos); }); });