React and Electron

When I first used Electron in 2015 it was not yet clear that it would be so pervasive in modern apps, and I was kind of shocked by the resulting app size.

But, Electron is clearly here to stay and it’s not mandatory that your app should feel slow and consume tons of memory, like VS Code demonstrates every day to me (on a not blazing fast machine).

So, here’s a quick start for a React app with create-react-app, ready to roll with ESlint integration.

Install npm if you haven’t already

On OSX:

brew install npm

Move to your development folder

cd ~/dev

Create react app

npx create-react-app app
cd app

Add electron

npm install electron
npm install electron-builder -D

Install foreman to allow executing the app from command line

npm install foreman -g

Install the create-react-app dependencies

npm install

Configure eslint (your mileage might vary)

.eslintrc.json

{
    "env": {
        "browser": true,
        "commonjs": true,
        "es6": true,
        "jest": true
    },
    "parserOptions": {
        "ecmaFeatures": {
            "jsx": true
        },
        "sourceType": "module"
    },
    "rules": {
        "no-const-assign": "warn",
        "no-this-before-super": "warn",
        "no-undef": "warn",
        "no-continue": "off",
        "no-unreachable": "warn",
        "no-unused-vars": "warn",
        "constructor-super": "warn",
        "valid-typeof": "warn",
        "quotes": [
            2,
            "single"
        ],
        "semi": [
            "error",
            "never"
        ]
    },
    "parser": "babel-eslint",
    "extends": "airbnb",
    "plugins": [
        "react",
        "jsx-a11y",
        "import"
    ]
}

Now add ESLint and some of its helpers

npm install eslint eslint-config-airbnb eslint-plugin-jsx-a11y eslint-plugin-import eslint-plugin-react eslint-plugin-import

This is what you should have right now:

Create React App with Electron

Now tweak the package.json file to add some electron helpers.

Right now its content is something like

{
  "name": "gitometer",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "electron": "^1.7.5",
    "eslint": "^4.5.0",
    "eslint-config-airbnb": "^15.1.0",
    "eslint-plugin-import": "^2.7.0",
    "eslint-plugin-jsx-a11y": "^6.0.2",
    "eslint-plugin-react": "^7.3.0",
    "react": "^15.6.1",
    "react-dom": "^15.6.1",
    "react-scripts": "1.0.11"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  },
  "devDependencies": {
    "electron-builder": "^19.24.1"
  }
}

(don’t mind versions, outdated as soon as I publish this)

Remove the scripts property and change it with

  "scripts": {
    "start": "nf start -p 3000",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
    "electron": "electron .",
    "electron-start": "node src/electron-wait-react",
    "react-start": "BROWSER=none react-scripts start",
    "pack": "build --dir",
    "dist": "npm run build && build",
    "postinstall": "install-app-deps"
  },

As you can see, start was moved to react-start, but the rest is unchanged, and some electron utils were added.

BROWSER=none in react-start tells React not to load in a browser tab, so we only get the app in the Electron window.

Also add

  "homepage": "./",
  "main": "src/electron-starter.js",

and

  "build": {
    "appId": "com.electron.electron-with-create-react-app",
    "win": {
      "iconUrl": "https://cdn2.iconfinder.com/data/icons/designer-skills/128/react-256.png"
    },
    "directories": {
      "buildResources": "public"
    }
  }

The end result should be:

{
  "name": "gitometer",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "electron": "^1.7.5",
    "eslint": "^4.5.0",
    "eslint-config-airbnb": "^15.1.0",
    "eslint-plugin-import": "^2.7.0",
    "eslint-plugin-jsx-a11y": "^6.0.2",
    "eslint-plugin-react": "^7.3.0",
    "react": "^15.6.1",
    "react-dom": "^15.6.1",
    "react-scripts": "1.0.11"
  },
  "devDependencies": {
    "electron-builder": "^19.24.1"
  },
  "homepage": "./",
  "main": "src/start.js",
  "scripts": {
    "start": "nf start -p 3000",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
    "electron": "electron .",
    "electron-start": "node src/start-react",
    "react-start": "BROWSER=none react-scripts start",
    "pack": "build --dir",
    "dist": "npm run build && build",
    "postinstall": "install-app-deps"
  },
  "build": {
    "appId": "com.electron.electron-with-create-react-app",
    "win": {
      "iconUrl": "https://cdn2.iconfinder.com/data/icons/designer-skills/128/react-256.png"
    },
    "directories": {
      "buildResources": "public"
    }
  }
}

Now create a file named Procfile in the project root folder, with this content:

react: npm run react-start
electron: npm run electron-start

Enough with the setup!

Let’s now start writing some code.

src/start.js

const electron = require('electron')
const app = electron.app
const BrowserWindow = electron.BrowserWindow

const path = require('path')
const url = require('url')

let mainWindow

function createWindow() {
  mainWindow = new BrowserWindow({ width: 800, height: 600 })

  mainWindow.loadURL(
    process.env.ELECTRON_START_URL ||
      url.format({
        pathname: path.join(__dirname, '/../build/index.html'),
        protocol: 'file:',
        slashes: true
      })
  )

  mainWindow.on('closed', () => {
    mainWindow = null
  })
}

app.on('ready', createWindow)

app.on('window-all-closed', () => {
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', () => {
  if (mainWindow === null) {
    createWindow()
  }
})

src/start-react.js

const net = require('net')
const childProcess = require('child_process')

const port = process.env.PORT ? process.env.PORT - 100 : 3000

process.env.ELECTRON_START_URL = `http://localhost:${port}`

const client = new net.Socket()

let startedElectron = false
const tryConnection = () => {
  client.connect(
    { port },
    () => {
      client.end()
      if (!startedElectron) {
        console.log('starting electron')
        startedElectron = true
        const exec = childProcess.exec
        exec('npm run electron')
      }
    }
  )
}

tryConnection()

client.on('error', () => {
  setTimeout(tryConnection, 1000)
})

Start up

That’s it!

Run

npm start

and you should see the React sample app coming up in a native app:

React Sample in Electron

Thanks to

This post was heavily inspired by https://gist.github.com/matthewjberger/6f42452cb1a2253667942d333ff53404