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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.

class WebSocket extends EventTarget {

constructor(url: string, protocols?: string | string[]);

binaryType: BinaryType;

readonly bufferedAmount: number;

readonly CLOSED: number;

readonly CLOSING: number;

readonly CONNECTING: number;

readonly extensions: string;

onclose: ((this: WebSocket, ev: CloseEvent) => any) | null;

onerror: ((this: WebSocket, ev: Event | ErrorEvent) => any) | null;

onmessage: ((this: WebSocket, ev: MessageEvent) => any) | null;

onopen: ((this: WebSocket, ev: Event) => any) | null;

readonly OPEN: number;

readonly protocol: string;

readonly readyState: number;

readonly url: string;

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;

close(code?: number, reason?: string): void;

removeEventListener<K extends keyof WebSocketEventMap>(

type: K,

listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any,

options?: boolean | EventListenerOptions,

): void;

removeEventListener(

type: string,

listener: EventListenerOrEventListenerObject,

options?: boolean | EventListenerOptions,

): void;

send(data:

| string

| ArrayBufferLike

| Blob

| ArrayBufferView

): void;

static readonly CLOSED: number;

static readonly CLOSING: number;

static readonly CONNECTING: number;

static readonly OPEN: number;

}

Extends

EventTarget

Constructors

new WebSocket(url: string, protocols?: string | string[])

Properties

binaryType: BinaryType

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".

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.)

CLOSED: number

CLOSING: number

CONNECTING: number

extensions: string

Returns the extensions selected by the server, if any.

onclose: ((this: WebSocket, ev: CloseEvent) => any) | null

onerror: ((this: WebSocket, ev: Event | ErrorEvent) => any) | null

onmessage: ((this: WebSocket, ev: MessageEvent) => any) | null

onopen: ((this: WebSocket, ev: Event) => any) | null

OPEN: number

protocol: string

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.

url: string

Returns the URL that was used to establish the WebSocket connection.

Methods

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

close(code?: number, reason?: string): void

Closes the WebSocket connection, optionally using code as the the WebSocket connection close code and reason as the the WebSocket connection close reason.

removeEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | EventListenerOptions): void

removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void

send(data: string | ArrayBufferLike | Blob | ArrayBufferView): void

Transmits data using the WebSocket connection. data can be a string, a Blob, an ArrayBuffer, or an ArrayBufferView.

Static Properties

CLOSED: number

CLOSING: number

CONNECTING: number

OPEN: number