Symbol

WebSocket

class WebSocket

A WebSocket client implementation

const ws = new WebSocket("ws://localhost:8080", {
 headers: {
   "x-custom-header": "hello",
 },
});

ws.addEventListener("open", () => {
  console.log("Connected to server");
});

ws.addEventListener("message", (event) => {
  console.log("Received message:", event.data);
});

ws.send("Hello, server!");
ws.terminate();

binaryType: 'arraybuffer' | 'nodebuffer'
The type of binary data being received.
readonly bufferedAmount: number
The number of bytes of data that have been queued using send() but not yet transmitted to the network
readonly extensions: string
The extensions selected by the server
onclose: null | (this: WebSocket, ev: CloseEvent) => any
Event handler for close event
onerror: null | (this: WebSocket, ev: Event) => any
Event handler for error event
onmessage: null | (this: WebSocket, ev: new (type: string, eventInitDict?: MessageEventInit<T>) => MessageEvent<T>) => any
Event handler for message event
onopen: null | (this: WebSocket, ev: Event) => any
Event handler for open event
readonly protocol: string
The protocol selected by the server
readonly readyState: 0 | 1 | 2 | 3
The current state of the connection
readonly url: string
The URL of the WebSocket connection
readonly static CLOSED: 3
readonly static CLOSING: 2
readonly static CONNECTING: 0
readonly static OPEN: 1
addEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void
Registers an event handler of a specific event type on the WebSocket.
@param type
A case-sensitive string representing the event type to listen for
@param listener
The function to be called when the event occurs
@param options
An options object that specifies characteristics about the event listener
addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void
Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.
The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.
When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.
When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.
When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.
If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.
The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.
MDN Reference
close(code?: number, reason?: string): void
Closes the WebSocket connection
@param code
A numeric value indicating the status code
@param reason
A human-readable string explaining why the connection is closing
dispatchEvent(event: Event): boolean
Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.
ping(data?: string | ArrayBufferLike | ArrayBufferView<ArrayBufferLike>): void
Sends a ping frame to the server
@param data
Optional data to include in the ping frame
pong(data?: string | ArrayBufferLike | ArrayBufferView<ArrayBufferLike>): void
Sends a pong frame to the server
@param data
Optional data to include in the pong frame
removeEventListener<K extends keyof WebSocketEventMap>(type: K, listener: (this: WebSocket, ev: WebSocketEventMap[K]) => any, options?: boolean | EventListenerOptions): void
Removes an event listener previously registered with addEventListener()
@param type
A case-sensitive string representing the event type to remove
@param listener
The function to remove from the event target
@param options
An options object that specifies characteristics about the event listener
removeEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | EventListenerOptions): void
Removes the event listener in target's event listener list with the same type, callback, and options.
MDN Reference
send(data: string | ArrayBufferLike | ArrayBufferView<ArrayBufferLike>): void
Transmits data to the server
@param data
The data to send to the server
terminate(): void
Immediately terminates the connection