Angular 4 + Electron - How to run application and watch for changes (live reload)

Question

I am creating an Electron application using Angular 4. How can i set it up so that it watches for any changes and live reloads it.

package.json

{
  "name": "angular-electron",
  "version": "0.0.0",
  "license": "MIT",
  "main": "main.js",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e",
    "electron": "electron .",
    "electron-build": "ng build --prod && electron ."
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^4.2.4",
    "@angular/common": "^4.2.4",
    "@angular/compiler": "^4.2.4",
    "@angular/core": "^4.2.4",
    "@angular/forms": "^4.2.4",
    "@angular/http": "^4.2.4",
    "@angular/platform-browser": "^4.2.4",
    "@angular/platform-browser-dynamic": "^4.2.4",
    "@angular/router": "^4.2.4",
    "angular-svg-round-progressbar": "^1.1.0",
    "bulma": "^0.5.3",
    "core-js": "^2.4.1",
    "rxjs": "^5.4.2",
    "zone.js": "^0.8.14"
  },
  "devDependencies": {
    "@angular/cli": "1.4.1",
    "@angular/compiler-cli": "^4.2.4",
    "@angular/language-service": "^4.2.4",
    "@types/jasmine": "~2.5.53",
    "@types/jasminewd2": "~2.0.2",
    "@types/node": "~6.0.60",
    "codelyzer": "~3.1.1",
    "electron": "^1.7.6",
    "electron-packager": "^9.1.0",
    "jasmine-core": "~2.6.2",
    "jasmine-spec-reporter": "~4.1.0",
    "karma": "~1.7.0",
    "karma-chrome-launcher": "~2.1.1",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^1.2.1",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.2",
    "ts-node": "~3.2.0",
    "tslint": "~5.3.2",
    "typescript": "~2.3.3"
  }
}

electron

const { app, BrowserWindow } = require('electron')

let win;

function createWindow () {
  // Create the browser window.
  win = new BrowserWindow({
    width: 600, 
    height: 600,
    backgroundColor: '#ffffff',
    icon: `file://${__dirname}/dist/assets/logo.png`
  })

  win.loadURL(`file://${__dirname}/dist/index.html`)

  //// uncomment below to open the DevTools.
  // win.webContents.openDevTools()

  // Event when the window is closed.
  win.on('closed', function () {
    win = null
  })
}

// Create window on electron intialization
app.on('ready', createWindow)

// Quit when all windows are closed.
app.on('window-all-closed', function () {

  // On macOS specific close process
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', function () {
  // macOS specific close process
  if (win === null) {
    createWindow()
  }
})

thanks.

Currently, i build my application every time using the following command

ng build --prod && electron .

This gets tiring, so i want to be able to build run one command so it watches for changes and live reloads.

Answer 1

You can use electron-reload for hot module reload. It listens on file changes and reloads the electron app.

Simply add it to the devDependencies in your package.json.

Then, you have to add it to your main.ts:

import { app, BrowserWindow, Menu } from 'electron';

let win, serve;
const args = process.argv.slice(1);
serve = args.some(val => val === '--serve');

if (serve) {
  require('electron-reload')(__dirname, {});
}

Then add a command to your package json

"start": "webpack --watch",
"serve": "npm run build:main && electron ./dist --serve",
"build:main": "tsc main.ts --outDir dist && copyfiles package.json dist && cd dist && npm install --prod"

where build:main is your build script to compile your project. This compiles all Typescript files and puts them into the dist folder. Afterwards, it runs npm install to download and install modules from NPM.

You need the module-bundler Webpack for this to run. Install it with

npm install --save-dev webpack

First, in a console run npm start. Afterwards, in a second console executenpm run serve. Now, it listens for changes and recompiles on file changes.

tsc stands for TypeScript compiler. If you're using tsc as a node module, make sure its installed:

npm install -g typescript

I use it currently for a project with the same setup (Angular 4, Electron) and it works perfectly.

Answer 2

I personally hate pretty much all other answers out there on the internet. I chose to do something more off the wall. I do ALL development with just raw angular, and stub out the parts of the application that require electron things, like sharing the desktop, or getting a config file from somewhere like this:

if (!this.electron.isElectronApp) {
  return {
    config:data,
    more:data,
  }
} else {
  do electron things
}

It so far has worked wonderfully. If can anyone think how this is going to bite me in the butt later please share.