Hot Reload in ElectronJs

Hot reloading is a powerful feature in ElectronJS that lets developers quickly view their code changes in real time without having to restart the application. It makes the development process faster and more efficient by reducing the time and effort required to test changes.

Steps to Implement Hot Reload in ElectronJS

The hot reloading feature is implemented using a library called “electron-reload”, and it can be easily integrated into an Electron JS application by following a few simple steps. Users can follow the steps below to implement hot reload in Electron Js −

Install the electron-reload module

The first step in implementing hot reload in Electron JS is to install the electron-reload module. Users can install it using npm as follows −

npm install electron-reload 

Require electron-reload in the main process

Once the electron-reload module is installed, we need to require it in the main process of our Electron application. We can do it by adding the following code to our main.js file −

const electronReload = require('electron-reload');
electronReload(__dirname);

Reload the renderer process

The final step is to reload the renderer process whenever there is a change in our code. We can do it by adding the following code to our renderer.js file −

if (module.hot) {
   module.hot.accept();
}

Advanced Usage and Customization Options for Hot Reloading

Hot reloading in Electron is easy to set up, but the “electron-reload” module offers extra options like ignoring specific files and folders and excluding certain modules from reloading.

Important Functions for Implementing Hot Reloading in ElectronJS

In hot reloading, there are a few important functions to understand in order to implement it in our Electron application −

module.hot.accept() − This function is used in the renderer process to enable hot reloading for the renderer process. When a change is made to the renderer process code, the renderer process will be reloaded automatically, and the changes will be reflected in the application in real-time.

electronReload(__dirname) − This function is used in the main process to enable hot reloading for the main process. It reloads the main process whenever a change is made to the code, allowing us to see the effects of our changes in real time.

app.on('ready', () => {...}) − This event handler function is called when the Electron application is ready to be displayed to the user. It's typically used to create the main window and load the initial HTML file.

BrowserWindow − This class is used to create new windows in the Electron application. In the main process, we can create instances of BrowserWindow and set various options, such as the size and web preferences, to customize the appearance and behavior of each window.

These functions are key to understanding how hot reloading works in Electron JS and are used in the examples provided earlier in this tutorial. By understanding how to use these functions, we can implement hot reloading in our Electron applications and make changes to both the main process and renderer process in real-time.

Example

In this example , first we use the electron.app module to create a new ElectronJS application and use the on method to register a callback function that is triggered when the application is ready. In this callback function, we create a new browser window using the electron.BrowserWindow module and load an index.html file into it.

Next, in the renderer.js file , we use the module.hot property to enable hot reloading in the renderer process. This way, if we make any changes to the renderer.js file, the updated code will be reloaded automatically.

Finally, we use console.log to log the message "Hello World!" to the console.

The index.html file is a simple HTML file that displays a header and a paragraph and serves as the application's UI.

main.js

// main.js 
const { app, BrowserWindow } = require('electron');
const electronReload = require('electron-reload');
electronReload(__dirname);
let win;
app.on('ready', () => {
   win = new BrowserWindow({
      width: 800,
      height: 600,
      webPreferences: {
         nodeIntegration: true
      }
   });
   win.loadFile('index.html');
}); 

renderer.js

// renderer.js
if (module.hot) {
   module.hot.accept();
}
document.getElementById('root').innerHTML = 'Hello, Hot Reloading!'; 

index.html

<html lang = "en" >
<head>
   <title> Electorn Js </title>
</head>
<body> 
   <h2> Hot Reload in ElectornJs </h2>
   <p> With hot reloading enabled, any changes made to the code in the "main.js" or "renderer.js" files will be reflected in the application in real-time without requiring a full restart of the application. </p>
</body>
 </html>

Example

In this example ,the electronJs app is set to create a new window when the "ready" event is fired, and the window loads the index.html file.

The “renderer.js” file contains a hot module reload (HMR) statement, which reloads the renderer process whenever changes are made to the code. It also logs "Hello World!" to the console.

And the “index.html” file displays a heading and a paragraph, indicating that hot reload is enabled.

main.js

// main.js
const electron = require('electron');
const electronReload = require('electron-reload');
electronReload(__dirname);
const app = electron.app;
app.on('ready', createWindow);

function createWindow () {
   
   // Create the browser window.
   const win = new electron.BrowserWindow({
      width: 800,
      height: 600,
      webPreferences: {
         nodeIntegration: true
      }
   })

   // and load the index.html of the app.
   win.loadFile('index.html')
} 

renderer.js

// renderer.js
if (module.hot) {
   module.hot.accept();
}
console.log('Hello World!');

index.html

<html>
<head>
   <title> Electorn Js </title>
</head>
<body>
   <h2> Hot Reload Enabled </h2>
   <p> Hot reloading allows for a faster development experience as we can see the effects of our changes immediately. </p>
</body>
</html>

In this tutorial, Users learned about the hot reload feature in ElectronJS and how it can make development process faster and more efficient by allowing developers to see the effects of their code changes in real time without having to restart the entire application.

Users also learned about the key functions and steps involved in implementing hot reloading in ElectronJS, such as requiring the electron-reload module in the main process, reloading the renderer process, and understanding the functions such as module.hot.accept(), electronReload(__dirname), app.on('ready', () => {...}), and BrowserWindow. By following these steps and understanding these key functions, Users can implement hot reloading in our ElectronJS applications and make changes to both the main process and renderer process in real-time.