結合Electron + React來開發跨平台的桌面程式

George Chang

Published in

origino

9 min readAug 21, 2017

English Title: A Minimal Desktop Application by using Electron with React

概念介紹

最近有一個需求想要實作跨平台的桌面軟體，便想藉此機會試試之前調查過的Electron，它的原名叫做Atom Shell，是Github團隊的開源框架，目前已經被很多知名公司拿來開發桌面軟體，包括Github的Atom、Slack與MS的Visual Studio Code。

它結合了Nodejs與Chromium，使得開發者能使用前端語言來開發桌面軟體，這篇文章用來紀錄安裝一個最基本的Electron+React的幾個步驟。

就我所知，與我較熟悉的WPF相比的話，WPF的效能還是比較好的，不過WPF只能限定在Windows平台運作，我想比起這個，開發速度與可維護性會重要的多。

名詞解釋

Electron: 本文使用的桌面應用程式框架。
Node.js: Javascript的後端執行環境。
NPM: Node.js的package manager。
Webpack: Javascript的模組打包工具，主要是為了編譯檔案轉成瀏覽器可執行的Javascript。
React: 由Facebook開發的Javascript函式庫。
Babel: Javascript編譯器，簡單的說你可以寫新標準的JS，然後用編譯器轉成瀏覽器支援的版本。

實際操作

先建立專案目錄：

$ mkdir electron101 && cd electron101

一個最基本的Electron app至少要有以下3個檔案

electron101

— index.html

— main.js

— package.json

建立package.json用來管理專案的套件與版本：

$ npm init -y

安裝electron

npm install electron --save-dev

建立main.js檔案，我這裡是參考electron-quick-start的main.js

const electron = require('electron')
// Module to control application life.
const app = electron.app
// Module to create native browser window.
const BrowserWindow = electron.BrowserWindowconst path = require('path')
const url = require('url')// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let mainWindowfunction createWindow () {
  // Create the browser window.
  mainWindow = new BrowserWindow({width: 800, height: 600})// and load the index.html of the app.
  mainWindow.loadURL(url.format({
    pathname: path.join(__dirname, 'index.html'),
    protocol: 'file:',
    slashes: true
  }))// Open the DevTools.
  // mainWindow.webContents.openDevTools()// Emitted when the window is closed.
  mainWindow.on('closed', function () {
    // Dereference the window object, usually you would store windows
    // in an array if your app supports multi windows, this is the time
    // when you should delete the corresponding element.
    mainWindow = null
  })
}// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on('ready', createWindow)// Quit when all windows are closed.
app.on('window-all-closed', function () {
  // On OS X it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform !== 'darwin') {
    app.quit()
  }
})app.on('activate', function () {
  // On OS X it's common to re-create a window in the app when the
  // dock icon is clicked and there are no other windows open.
  if (mainWindow === null) {
    createWindow()
  }
})// In this file you can include the rest of your app's specific main process
// code. You can also put them in separate files and require them here.

可以看到main.js內建立了electron.app與BrowserWindow，以及視窗事件對應的functions。

建立index.html

<!DOCTYPE html>
<html>
  <head>
    <title>Hello World</title>
  </head>
  <body>
    <div id="hello"></div>
  </body>
  <script src="./bundle.js"></script>
<html>

在index.html會看到尾部有引用一個javascript檔案 bundle.js ，這個檔案會在後面由webpack產生。

修改package.json的“main”，加入scripts：

{
  "name": "electron101",
  "version": "0.1.0",
  "description": "A Minimal Electron App",
  "main": "main.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "babel": "babel",
    "webpack": "webpack",
    "start": "electron ."
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-core": "^6.26.0",
    "babel-loader": "^7.1.2",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "electron": "^1.7.5",
    "react": "^15.6.1",
    "react-dom": "^15.6.1",
    "webpack": "^3.5.5"
  }
}

安裝Webpack

npm install webpack --save-dev

安裝Babel

npm install babel-loader babel-core babel-preset-es2015 babel-preset-react --save-dev

安裝React與React-dom

npm install react --save-dev
npm install react-dom --save-dev

建立webpack.config.js

var path = require('path');
var webpack = require('webpack');module.exports = {
  entry: './app.js',
  output: {path: __dirname, filename: 'bundle.js' },
 
  module: {
    loaders: [
      {
        test: /.jsx?$/,
        loader: 'babel-loader',
        exclude: /node_modules/,
        query: {
          presets: ['es2015', 'react']
        }
      }
    ]
  },
};

這裡會看到entry為app.js

建立app.js

import React from 'react'
import ReactDOM from 'react-dom'
 
var HomeMessage = React.createClass({
 
  render: function() {
    return (
      <div className="hello">
        Hello world
      </div>
    );
  }
});ReactDOM.render(<HomeMessage/>, document.getElementById('hello'));

接著在package.json的scripts區段加入：

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "electron .",
    "babel": "babel",
    "webpack": "webpack"
  },

執行webpack打包成可執行的javascript