lukeed/sockette

Sockette

Sockette is a tiny (367 bytes) wrapper around WebSocket that will automatically reconnect if the connection is lost!

In addition to attaching additional API methods, Sockette allows you to reuse instances, avoiding the need to redeclare all event listeners.

You have direct access to the (current) underlying WebSocket within every EventListener callback (via event.target).

Install

$ npm install --save sockette

Usage

Unlike WebSocket, you should declare all event listeners on initialization:

const Sockette = require('sockette');

const ws = new Sockette('ws://localhost:3000', {
  timeout: 5e3,
  maxAttempts: 10,
  onopen: e => console.log('Connected!', e),
  onmessage: e => console.log('Received:', e),
  onreconnect: e => console.log('Reconnecting...', e),
  onmaximum: e => console.log('Stop Attempting!', e),
  onclose: e => console.log('Closed!', e),
  onerror: e => console.log('Error:', e)
});

ws.send('Hello, world!');
ws.json({type: 'ping'});
ws.close(); // graceful shutdown

// Reconnect 10s later
setTimeout(ws.reconnect, 10e3);

API

Sockette(url, options)

Returns: Sockette

Returns the Sockette instance.

url

Type: String

The URL you want to connect to — Should be prefixed with ws:// or wss://. This is passed directly to WebSocket.

options.protocols

Type: String|Array

Either a single protocol string or an array of strings used to indicate sub-protocols. See the WebSocket docs for more info.

options.timeout

Type: Number
Default: 1000

The amount of time (in ms) to wait in between reconnection attempts. Defaults to 1 second.

options.maxAttempts

Type: Number
Default: Infinity

The maximum number of attempts to reconnect.

Important: Pass -1 if you want to disable this feature. Although, this is main reason to use Sockette! :joy:

options.onopen

Type: Function

The EventListener to run in response to 'open' events. It receives the Event object as its only parameter.

This is called when the connection has been established and is ready to send and receive data.

Important: Sockette will forget the number of previous reconnection attempts, so that the next time connection is lost, you will consistently retry n number of times, as determined by options.maxAttempts.

options.onmessage

Type: Function

The EventListener to run in response to 'message' events. It receives the Event object as its only parameter.

This is called when a message has been received from the server. You'll probably want event.data!

options.onreconnect

Type: Function

The callback to run when attempting to reconnect to the server.

If Sockette is automatically reconnecting in response to an error or unexpected close event, then your onreconnect callback will receive the forwarded Event object.

options.onmaximum

Type: Function

The callback to run when the maxAttempts limit has been met.

This callback will receive the forwarded Event object from onclose.

options.onclose

Type: Function

The EventListener to run in response to 'close' events. It receives the Event object as its only parameter.

This is called when the connection has been closed for any reason.

Important: If the event.code is not 1000, 1001, or 1005 an automatic reconnect attempt will be queued.

options.onerror

Type: Function

The EventListener to run in response to 'error' events. It receives the Event object as its only parameter.

This is called anytime an error occurs.

Important: If the event.code is ECONNREFUSED, an automatic reconnect attempt will be queued.

send(data)

Identical to WebSocket.send(), capable of sending multiple data types.

close(code, reason)

Identical to WebSocket.close().

Note: The code will default to 1000 unless specified.

json(obj)

Convenience method that passes your obj (Object) through JSON.stringify before passing it to WebSocket.send().

reconnect()

If options.maxAttempts has not been exceeded, enqueues a reconnection attempt. Otherwise, it runs your options.onmaximum callback.

open()

Initializes a new WebSocket — used on initialization and by reconnect().

License

MIT © Luke Edwards