Documentation / @eventkit/http / WebSocket

Class: WebSocket

A drop-in replacement for the standard WebSocket class that provides an Observable interface for handling WebSocket connections. This class extends the native WebSocket class and adds the ability to consume events as an AsyncObservable using the asObservable method.

Example

import { WebSocket } from "@eventkit/http";

const ws = new WebSocket("wss://api.example.com/ws");

// Get raw message data
ws.asObservable<string>().subscribe(data => {
  console.log("Received:", data);
});

// Get full event objects including metadata
ws.asObservable<string>({ dematerialize: true }).subscribe(event => {
  switch (event.type) {
    case "message":
      console.log("Message:", event.data.data);
      break;
    case "error":
      console.error("Error:", event.data);
      break;
    case "close":
      console.log("Connection closed:", event.data.code, event.data.reason);
      break;
    case "open":
      console.log("Connection opened");
      break;
  }
});

See

MDN Reference

Extends

• WebSocket

Constructors

Constructor

new WebSocket(url, protocols?): WebSocketObservable

Parameters

Parameter	Type
url	string | URL
protocols?	string | string[] | WebSocketInit

Returns

WebSocketObservable

Inherited from

WebSocket.constructor

Properties

binaryType

binaryType: BinaryType;

Inherited from

WebSocket.binaryType

---

bufferedAmount

readonly bufferedAmount: number;

Inherited from

WebSocket.bufferedAmount

---

CLOSED

readonly CLOSED: number;

Inherited from

WebSocket.CLOSED

---

CLOSING

readonly CLOSING: number;

Inherited from

WebSocket.CLOSING

---

CONNECTING

readonly CONNECTING: number;

Inherited from

WebSocket.CONNECTING

---

extensions

readonly extensions: string;

Inherited from

WebSocket.extensions

---

onclose

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

Inherited from

WebSocket.onclose

---

onerror

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

Inherited from

WebSocket.onerror

---

onmessage

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

Inherited from

WebSocket.onmessage

---

onopen

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

Inherited from

WebSocket.onopen

---

OPEN

readonly OPEN: number;

Inherited from

WebSocket.OPEN

---

protocol

readonly protocol: string;

Inherited from

WebSocket.protocol

---

readyState

readonly readyState: number;

Inherited from

WebSocket.readyState

---

url

readonly url: string;

Inherited from

WebSocket.url

---

CLOSED

readonly static CLOSED: number;

Inherited from

WebSocket.CLOSED

---

CLOSING

readonly static CLOSING: number;

Inherited from

WebSocket.CLOSING

---

CONNECTING

readonly static CONNECTING: number;

Inherited from

WebSocket.CONNECTING

---

OPEN

readonly static OPEN: number;

Inherited from

WebSocket.OPEN

Methods

addEventListener()

Call Signature

addEventListener<K>(
   type, 
   listener, 
   options?): void

Adds a new handler for the type event. Any given listener is added only once per type and per capture option value.

If the once option is true, the listener is removed after the next time a type event is dispatched.

The capture option is not used by Node.js in any functional way other than tracking registered event listeners per the EventTarget specification. Specifically, the capture option is used as part of the key when registering a listener. Any individual listener may be added once with capture = false, and once with capture = true.

Type Parameters

Type Parameter
K extends keyof WebSocketEventMap

Parameters

Parameter	Type
type	K
listener	(this, ev) => any
options?	boolean | AddEventListenerOptions

Returns

void

Inherited from

WebSocket.addEventListener

Call Signature

addEventListener(
   type, 
   listener, 
   options?): void

Adds a new handler for the type event. Any given listener is added only once per type and per capture option value.

If the once option is true, the listener is removed after the next time a type event is dispatched.

The capture option is not used by Node.js in any functional way other than tracking registered event listeners per the EventTarget specification. Specifically, the capture option is used as part of the key when registering a listener. Any individual listener may be added once with capture = false, and once with capture = true.

Parameters

Parameter	Type
type	string
listener	EventListenerOrEventListenerObject
options?	boolean | AddEventListenerOptions

Returns

void

Inherited from

WebSocket.addEventListener

---

asObservable()

Call Signature

asObservable<T>(opts): AsyncObservable<WebSocketEvent<T>>

Converts the WebSocket into an AsyncObservable that yields either raw message data or full event objects depending on the options provided.

Type Parameters

Type Parameter	Description
T	The type of data contained in message events

Parameters

Parameter	Type	Description
opts	{ dematerialize: true; }	Configuration options for the observable
opts.dematerialize	true	When true, yields full event objects including metadata. When false or omitted, yields only the message data.

Returns

AsyncObservable<WebSocketEvent<T>>

An AsyncObservable that yields either raw message data or full event objects

Call Signature

asObservable<T>(opts?): AsyncObservable<T>

Converts the WebSocket into an AsyncObservable that yields either raw message data or full event objects depending on the options provided.

Type Parameters

Type Parameter	Description
T	The type of data contained in message events

Parameters

Parameter	Type	Description
opts?	{ dematerialize: false; }	Configuration options for the observable
opts.dematerialize?	false	When true, yields full event objects including metadata. When false or omitted, yields only the message data.

Returns

AsyncObservable<T>

An AsyncObservable that yields either raw message data or full event objects

---

close()

close(code?, reason?): void

Parameters

Parameter	Type
code?	number
reason?	string

Returns

void

Inherited from

WebSocket.close

---

dispatchEvent()

dispatchEvent(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.

Parameters

Parameter	Type
event	Event

Returns

boolean

Inherited from

WebSocket.dispatchEvent

---

removeEventListener()

Call Signature

removeEventListener<K>(
   type, 
   listener, 
   options?): void

Removes the event listener in target's event listener list with the same type, callback, and options.

Type Parameters

Type Parameter
K extends keyof WebSocketEventMap

Parameters

Parameter	Type
type	K
listener	(this, ev) => any
options?	boolean | EventListenerOptions

Returns

void

Inherited from

WebSocket.removeEventListener

Call Signature

removeEventListener(
   type, 
   listener, 
   options?): void

Removes the event listener in target's event listener list with the same type, callback, and options.

Parameters

Parameter	Type
type	string
listener	EventListenerOrEventListenerObject
options?	boolean | EventListenerOptions

Returns

void

Inherited from

WebSocket.removeEventListener

---

send()

send(data): void

Parameters

Parameter	Type
data	string | ArrayBufferLike | Blob | ArrayBufferView<ArrayBufferLike>

Returns

void

Inherited from

WebSocket.send