How to set app icon for Electron / Atom Shell App

Below is the solution that I have :

new BrowserWindow({
  width: 800,
  height: 600,
  icon: __dirname + '/Bluetooth.ico',
})

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IMPORTANT: OUTDATED ANSWER, LOOK AT THE OTHER NEWER SOLUTIONS

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You can do it for macOS, too. Ok, not through code, but with some simple steps:

1. Find the .icns file you want to use, open it and copy it via Edit menu
2. Find the electron.app, usually in node_modules/electron/dist
3. Open the information window
4. Select the icon on the top left corner (gray border around it)
5. Paste the icon via cmd+v
6. Enjoy your icon during development :-)

Actually it is a general thing not specific to electron. You can change the icon of many macOS apps like this.

For Electron < 3.0 version. Updated package.json:

"build": {
  "appId": "com.my-website.my-app",
  "productName": "MyApp",
  "copyright": "Copyright © 2019 ${author}",
  "mac": {
    "icon": "./public/icons/mac/icon.icns",     <---------- set Mac Icons
    "category": "public.app-category.utilities"
  },
  "win": {
    "icon": "./public/icons/png/256x256.png" <---------- set Win Icon
  },
  "files": [
    "./build/**/*",
    "./dist/**/*",
    "./node_modules/**/*",
    "./public/**/*",       <---------- need for get access to icons
    "*.js"
  ],
  "directories": {
    "buildResources": "public" <---------- folder where placed icons
  }
},

After build application you can see icons. This solution don't show icons in developer mode. I don't setup icons in new BrowserWindow().

Setting the icon property when creating the BrowserWindow only has an effect on Windows and Linux.

To set the icon on OS X, you can use electron-packager and set the icon using the --icon switch.

It will need to be in .icns format for OS X. There is an online icon converter which can create this file from your .png.