interface WebSocket
Provides the API for creating and managing a WebSocket connection to a server, as well as for sending and receiving data on the connection.
If you are looking to create a WebSocket server, please take a look at
Deno.upgradeWebSocket().
Examples #
// Creating a WebSocket connection
const ws = new WebSocket("ws://localhost:8080");
// Setting up event handlers
ws.onopen = (event) => {
console.log("Connected to the server");
ws.send("Hello Server!");
};
ws.onmessage = (event) => {
console.log(`Received: ${event.data}`);
};
ws.onerror = (event) => {
console.error("WebSocket error observed:", event);
};
ws.onclose = (event) => {
console.log(`WebSocket closed: Code=${event.code}, Reason=${event.reason}`);
};
Properties #
Returns a string that indicates how binary data from the WebSocket object is exposed to scripts:
Can be set, to change how binary data is returned. The default is "blob".
const ws = new WebSocket("ws://localhost:8080");
ws.binaryType = "arraybuffer";
#bufferedAmount: number Returns the number of bytes of application data (UTF-8 text and binary data) that have been queued using send() but not yet been transmitted to the network.
If the WebSocket connection is closed, this attribute's value will only increase with each call to the send() method. (The number does not reset to zero once the connection closes.)
const ws = new WebSocket("ws://localhost:8080");
ws.send("Hello, world!");
console.log(ws.bufferedAmount); // 13
#extensions: string Returns the extensions selected by the server, if any.
WebSocket extensions add optional features negotiated during the handshake via
the Sec-WebSocket-Extensions header.
At the time of writing, there are two registered extensions:
permessage-deflate: Enables per-message compression using DEFLATE.bbf-usp-protocol: Used by the Broadband Forum's User Services Platform (USP).
See the full list at IANA WebSocket Extensions.
Example:
const ws = new WebSocket("ws://localhost:8080");
console.log(ws.extensions); // e.g., "permessage-deflate"
#onclose: ((this: WebSocket,ev: CloseEvent,) => any) | null #onerror: ((this: WebSocket,ev: Event | ErrorEvent,) => any) | null #onmessage: ((this: WebSocket,ev: MessageEvent,) => any) | null Returns the subprotocol selected by the server, if any. It can be used in conjunction with the array form of the constructor's second argument to perform subprotocol negotiation.
#readyState: number Returns the state of the WebSocket object's connection. It can have the values described below.
#CONNECTING: number Methods #
Closes the WebSocket connection, optionally using code as the WebSocket connection close code and reason as the WebSocket connection close reason.
Transmits data using the WebSocket connection. data can be a string, a Blob, an ArrayBuffer, or an ArrayBufferView.
#addEventListener<K extends keyof WebSocketEventMap>(type: K,listener: (this: WebSocket,ev: WebSocketEventMap[K],) => any,options?: boolean | AddEventListenerOptions,): void #addEventListener(type: string,listener: EventListenerOrEventListenerObject,options?: boolean | AddEventListenerOptions,): void #removeEventListener<K extends keyof WebSocketEventMap>(type: K,listener: (this: WebSocket,ev: WebSocketEventMap[K],) => any,options?: boolean | EventListenerOptions,): void #removeEventListener(): void See #
variable WebSocket
Constructor interface for creating WebSocket instances.
The WebSocket constructor creates and returns a new WebSocket object
that represents a connection to a WebSocket server.
Examples #
// Basic WebSocket connection
const ws = new WebSocket("ws://localhost:8080");
// WebSocket with protocol specification
const wsWithProtocol = new WebSocket("ws://localhost:8080", "json");
// WebSocket with multiple protocol options (server will select one)
const wsWithProtocols = new WebSocket("ws://localhost:8080", ["json", "xml"]);
// Using URL object instead of string
const url = new URL("ws://localhost:8080/path");
const wsWithUrl = new WebSocket(url);
// WebSocket with headers
const wsWithProtocols = new WebSocket("ws://localhost:8080", {
headers: {
"Authorization": "Bearer foo",
},
});