Ice Hot Reloader

@n8d/ice-hotreloader provides a lightweight WebSocket server designed to facilitate Hot Module Reloading (HMR) or live reloading for frontend development environments. It works in conjunction with build tools like @n8d/ice-build or other systems that can trigger reload messages.

Overview

This utility offers a simple way to push updates to connected browser clients when source files change:

• WebSocket Server: Starts a basic WebSocket server on a specified port.
• Client Broadcasting: Provides methods to send messages (e.g., "reload", "updateCSS") to all connected clients.
• Integration: Designed to be integrated into build pipelines or watch processes that detect file changes.

Installation

Install the package as a development dependency:

npm install --save-dev @n8d/ice-hotreloader
# or
yarn add --dev @n8d/ice-hotreloader

It typically requires a WebSocket implementation like ws:

npm install --save-dev ws
# or
yarn add --dev ws

Usage

The primary way to use this package is programmatically within a build script or watch process.

Example Integration (Conceptual):

import { HotReloadServer } from '@n8d/ice-hotreloader';
import chokidar from 'chokidar'; // Example file watcher

// Initialize the HMR server (e.g., on port 3001)
const hmrServer = new HotReloadServer(3001);
console.log(`Hot Reload Server listening on port ${hmrServer.port}`);

// Example: Watch for CSS file changes
chokidar.watch('path/to/your/css/**/*.css').on('change', (filePath) => {
  console.log(`CSS file changed: ${filePath}. Sending reload signal.`);
  // Send a message to clients to reload CSS or the whole page
  hmrServer.broadcast({ type: 'reloadCSS', path: filePath });
  // Or for a full page reload:
  // hmrServer.broadcast({ type: 'reloadPage' });
});

// Example: Watch for JS file changes
chokidar.watch('path/to/your/js/**/*.js').on('change', (filePath) => {
  console.log(`JS file changed: ${filePath}. Sending reload signal.`);
  // Send a message to clients to reload the page
  hmrServer.broadcast({ type: 'reloadPage' });
});

// Client-side JavaScript would need to connect to ws://localhost:3001
// and listen for these message types to perform the appropriate action.

API

new HotReloadServer(port: number)

Creates and starts a new WebSocket server instance on the given port.

hmrServer.broadcast(message: object)

Sends the message object (serialized as JSON) to all currently connected WebSocket clients.

hmrServer.port

Returns the port number the server is listening on.

hmrServer.close()

Closes the WebSocket server and disconnects all clients.

Client-Side Implementation

You need corresponding client-side JavaScript to connect to the WebSocket server and handle the messages sent by broadcast. A simple example:

const socket = new WebSocket('ws://localhost:3001'); // Use the correct port

socket.addEventListener('open', (event) => {
  console.log('Connected to Hot Reload server.');
});

socket.addEventListener('message', (event) => {
  try {
    const message = JSON.parse(event.data);
    console.log('HMR message received:', message);

    if (message.type === 'reloadPage') {
      console.log('Reloading page...');
      window.location.reload();
    } else if (message.type === 'reloadCSS') {
      console.log('Reloading CSS...');
      // Logic to find and reload the specific stylesheet or all stylesheets
      // Example: Find link tags and append a timestamp to the href
      document.querySelectorAll('link[rel="stylesheet"]').forEach(link => {
        const url = new URL(link.href);
        url.searchParams.set('_', Date.now());
        link.href = url.toString();
      });
    }
    // Add handlers for other message types as needed
  } catch (e) {
    console.error('Failed to parse HMR message:', e);
  }
});

socket.addEventListener('close', (event) => {
  console.log('Disconnected from Hot Reload server.');
});

socket.addEventListener('error', (event) => {
  console.error('WebSocket error:', event);
});