WebSocketConnection

Defined in: packages/core/src/data/streaming/websocket-connection.ts:62

WebSocket connection for bidirectional streaming.

Remarks

Provides real-time bidirectional communication with automatic reconnection. Unlike SSE, WebSocket supports sending data from client to server.

Features:

• Full-duplex communication
• JSON message parsing with text fallback
• Manual reconnection with exponential backoff
• Sub-protocol support
• Send capability with connection validation

Example

const ws = new WebSocketConnection({
  url: 'wss://api.example.com/stream',
  protocols: 'json',
});

ws.on('message', ({ data }) => {
  console.log('Received:', data);
});

await ws.connect();
ws.send({ type: 'subscribe', channel: 'updates' });

Extends

• BaseConnection

Constructors

Constructor

new WebSocketConnection(config): WebSocketConnection

Defined in: packages/core/src/data/streaming/websocket-connection.ts:79

Create a new WebSocket connection.

Parameters

Parameter	Type	Description
config	WebSocketConfig	WebSocket configuration

Returns

WebSocketConnection

Example

const connection = new WebSocketConnection({
  url: 'wss://api.example.com/stream',
  protocols: ['json', 'v1'],
});

Overrides

BaseConnection.constructor

Methods

connect()

connect(): Promise<void>

Defined in: packages/core/src/data/streaming/websocket-connection.ts:109

Establish WebSocket connection.

Returns

Promise<void>

Remarks

Creates a WebSocket and sets up event listeners for:

• Connection open
• Message reception
• Connection close
• Errors

Unlike EventSource, WebSocket does not have built-in reconnection, so reconnection is handled manually via the BaseConnection.

Throws

Error if WebSocket is not supported or connection fails

Example

await connection.connect();
console.log('Connected to WebSocket');

Overrides

BaseConnection.connect

---

disconnect()

disconnect(): void

Defined in: packages/core/src/data/streaming/websocket-connection.ts:176

Close WebSocket connection.

Returns

void

Remarks

Closes the WebSocket with a normal closure code (1000). Sets the manual disconnect flag to prevent automatic reconnection.

Example

connection.disconnect();
console.log('Disconnected from WebSocket');

Overrides

BaseConnection.disconnect

---

eventNames()

eventNames(): keyof ConnectionEvents[]

Defined in: packages/core/src/utils/event-emitter.ts:211

Get all event names that have registered handlers

Returns

keyof ConnectionEvents[]

Array of event names

Example

const events = emitter.eventNames();
console.log('Events with handlers:', events);

Inherited from

BaseConnection.eventNames

---

getReconnectAttempts()

getReconnectAttempts(): number

Defined in: packages/core/src/data/streaming/base-connection.ts:200

Get the number of reconnection attempts.

Returns

number

Number of reconnect attempts

Inherited from

BaseConnection.getReconnectAttempts

---

getState()

getState(): ConnectionState

Defined in: packages/core/src/data/streaming/base-connection.ts:175

Get current connection state.

Returns

ConnectionState

Current state

Example

const state = connection.getState();
if (state === 'connected') {
  // Connection is ready
}

Inherited from

BaseConnection.getState

---

hasListeners()

hasListeners<K>(event): boolean

Defined in: packages/core/src/utils/event-emitter.ts:228

Check if an event has any registered handlers

Type Parameters

Type Parameter
K extends keyof ConnectionEvents

Parameters

Parameter	Type	Description
event	K	Event name

Returns

boolean

True if the event has at least one handler

Example

if (emitter.hasListeners('message')) {
  emitter.emit('message', { text: 'Hello' });
}

Inherited from

BaseConnection.hasListeners

---

isConnected()

isConnected(): boolean

Defined in: packages/core/src/data/streaming/base-connection.ts:191

Check if connection is currently connected.

Returns

boolean

True if connected

Example

if (connection.isConnected()) {
  connection.send(data);
}

Inherited from

BaseConnection.isConnected

---

listenerCount()

listenerCount<K>(event): number

Defined in: packages/core/src/utils/event-emitter.ts:195

Get the number of handlers registered for an event

Type Parameters

Type Parameter
K extends keyof ConnectionEvents

Parameters

Parameter	Type	Description
event	K	Event name

Returns

number

Number of registered handlers

Example

const count = emitter.listenerCount('message');
console.log(`${count} handlers registered`);

Inherited from

BaseConnection.listenerCount

---

off()

off<K>(event, handler): void

Defined in: packages/core/src/utils/event-emitter.ts:120

Remove an event handler

Type Parameters

Type Parameter
K extends keyof ConnectionEvents

Parameters

Parameter	Type	Description
event	K	Event name
handler	EventHandler<ConnectionEvents[K]>	Handler function to remove

Returns

void

Example

const handler = (data) => console.log(data);
emitter.on('message', handler);
emitter.off('message', handler);

Inherited from

BaseConnection.off

---

on()

on<K>(event, handler): () => void

Defined in: packages/core/src/utils/event-emitter.ts:65

Register an event handler

Type Parameters

Type Parameter
K extends keyof ConnectionEvents

Parameters

Parameter	Type	Description
event	K	Event name to listen for
handler	EventHandler<ConnectionEvents[K]>	Callback function to invoke when event is emitted

Returns

Unsubscribe function that removes this specific handler

() => void

Example

const unsubscribe = emitter.on('message', (data) => {
  console.log(data.text);
});

// Later, to unsubscribe:
unsubscribe();

Inherited from

BaseConnection.on

---

once()

once<K>(event, handler): void

Defined in: packages/core/src/utils/event-emitter.ts:95

Register a one-time event handler

Type Parameters

Type Parameter
K extends keyof ConnectionEvents

Parameters

Parameter	Type	Description
event	K	Event name to listen for
handler	EventHandler<ConnectionEvents[K]>	Callback function to invoke once

Returns

void

Remarks

The handler will be automatically removed after being invoked once.

Example

emitter.once('connect', () => {
  console.log('Connected!');
});

Inherited from

BaseConnection.once

---

removeAllListeners()

removeAllListeners<K>(event?): void

Defined in: packages/core/src/utils/event-emitter.ts:175

Remove all handlers for an event, or all handlers for all events

Type Parameters

Type Parameter
K extends keyof ConnectionEvents

Parameters

Parameter	Type	Description
event?	K	Optional event name. If omitted, removes all handlers for all events.

Returns

void

Example

// Remove all handlers for 'message' event
emitter.removeAllListeners('message');

// Remove all handlers for all events
emitter.removeAllListeners();

Inherited from

BaseConnection.removeAllListeners

---

send()

send(data): void

Defined in: packages/core/src/data/streaming/websocket-connection.ts:198

Send data through WebSocket.

Parameters

Parameter	Type	Description
data	unknown	Data to send (will be JSON stringified)

Returns

void

Throws

Error if not connected

Remarks

The data is automatically converted to JSON before sending. Throws an error if called when the connection is not established.

Example

connection.send({ type: 'ping' });
connection.send({ type: 'subscribe', channel: 'updates' });