WebSocketEventsHandler

The WebSocketEventsHandler class is a comprehensive JavaScript handler for managing WebSocket connections, including automatic reconnection, heartbeat management, event handling, and offline event storage. This class provides robust support for WebSocket applications, ensuring seamless communication even in unstable network environments.

Features

• Automatic Reconnection: Attempts to reconnect with exponential backoff if the connection drops.
• Heartbeat Support: Regularly pings the server to maintain connection, with configurable intervals and timeouts.
• Event Handling: Allows registration of custom event handlers and triggers them on incoming messages.
• Local Event Storage: Caches events when offline and dispatches them once reconnected.
• Debug Mode: Logs detailed information about the WebSocket connection and events for troubleshooting.
• Network Detection: Listens for network status changes to handle online and offline events.

Installation

Install this module via npm:

1npm install ws-events-handler

Usage

Basic Initialization

1import WebSocketEventsHandler from './WebSocketEventsHandler';
2
3const wsHandler = new WebSocketEventsHandler('ws://your-websocket-url', {
4  heartbeat: { 
5    interval: 15000, 
6    message: 'ping', 
7    expectedResponse: 'pong', 
8    timeout: 10000 
9  },
10  connection: { 
11    maxRetries: 5, 
12    retryDelay: 1000 
13  },
14  debug: true
15});

Configuration Options

• heartbeat (object):

  • interval: Interval between heartbeats in milliseconds.
  • message: Message sent as heartbeat.
  • expectedResponse: Expected response from server.
  • timeout: Time to wait for a response before reconnecting.

• connection (object):

  • maxRetries: Maximum number of reconnection attempts.
  • retryDelay: Delay between reconnection attempts.
  • fallback.localEvents: Enable storing events locally when offline.

• debug (boolean): Enable verbose logging.

Event Handling

Register an event handler for a specific event:

1wsHandler.on('eventName', (data) => {
2  console.log('Event received:', data);
3});

Cyclic event handling

Register an event handler for a specific event in cycles.

1  wsEvents.on('eventName', { 
2    cycle: { 
3      every: 3,
4      exclusive: true,
5      once: true,
6      callback: (data) => {
7        console.log(data);
8      }
9    },
10    callback: (data) => {
11      console.log("this won't fire as cycle is configured to be exclusive.")
12    }
13  })

This configuration will fire callback once 3 messages for 'eventName' have arrived.

Configuration options for cycles

• every: Cycle will be executed every N messages.
• exclusive: Cycle will only execute it's internal callback and not the root callback defined in the handler configuration. If false, root callback will be called every time a message arrives to 'eventName'.
• rounds: Cycle will run N times and then it will self-destruct.
• once: Cycle will run only once. (similar to setting rounds = 1)

Unregister an event:

1wsHandler.off('eventName');

Sending Events

To send an event with optional payload:

1wsHandler.send('eventName', { key: 'value' });

Destroying the WebSocket Connection

To clean up resources and close the WebSocket connection:

1wsHandler.destroy('Reason for destruction');

Methods

• on(eventName, config): Registers an event handler.
• off(eventName): Unregisters an event handler.
• send(eventName, payload): Sends an event with an optional payload.
• destroy(reason): Destroys the WebSocket connection and cleans up resources.

License

This project is licensed under the MIT License.