socketio_client_typescript_strongly_typed_events_quickstart.ts

1import { io, Socket } from "socket.io-client";
2
3// Define the interface for events sent from the server to the client
4interface ServerToClientEvents {
5  noArg: () => void;
6  basicEmit: (a: number, b: string, c: Buffer) => void;
7  withAck: (d: string, callback: (e: number) => void) => void;
8}
9
10// Define the interface for events sent from the client to the server
11interface ClientToServerEvents {
12  hello: () => void;
13}
14
15// Initialize the socket with the defined types
16const socket: Socket<ServerToClientEvents, ClientToServerEvents> = io("https://server-domain.com");
17
18// Receiving an event (strongly typed)
19socket.on("noArg", () => {
20  console.log("No arguments received");
21});
22
23socket.on("basicEmit", (a, b, c) => {
24  // a is inferred as number, b as string, c as Buffer
25  console.log(a, b, c);
26});
27
28// Sending an event (strongly typed)
29socket.emit("hello");
30
31// Sending an event with acknowledgement
32socket.emit("hello", () => {
33  // logic after acknowledgement
34});