Below is the solution that I have :

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

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().

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IMPORTANT:OUTDATED ANSWER, LOOK AT THE OTHER NEWER SOLUTIONS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.

If you want to update the app icon in the taskbar, then Update following in main.js (if using typescript then main.ts)

win.setIcon(path.join(__dirname, '/src/assets/logo-small.png'));

__dirname points to the root directory (same directory as package.json) of your application.

In case you're converting an existing web app to an Electron app, you can use the following code:

const path = require('path')const mainWindow = new BrowserWindow({icon: path.join(__dirname, 'favicon.ico'),})

In my case, I don't need to specify any path such as ./, since I use build directory, and this is my configuration:

"build": {"directories":{"output": "build"},"mac": {"icon": "build/logo.icns"},"win": {"icon": "build/logo.png"}}

I found that using ./logo.png will make electron shows the same error:

default Electron icon is used reason=application icon is not set

electron-packager

To set the icon on OS X using electron-packager, 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.

electron-builder

1. Create a directory named build in your project directory and put the .icns the icon in the directory as named icon.icns.
2. run builder by executing command electron-builder --dir.

You will find your application icon will be automatically picked up from that directory location and used for an application while packaging.

Note: The given answer is for recent version of electron-builder and tested with electron-builder v21.2.0

win = new BrowserWindow({width: 1000, height: 1000,icon: __dirname + '/logo.png'}); //*.png or *.ico will also work 

in my case it worked !

windows 10

electron-packager

electron-packager . appname--platform=win32 --arch=x64 --overwrite --icon=icons/icon.ico --out=release-builds

the icon keeps getting cached, so using the --out flag helped.

Please be aware that the examples for icon file path tend to assume that main.js is under the base directory. If the file is not in the base directory of the app, the path specification must account for that fact.

For example, if the main.js is under the src/ subdirectory, and the icon is under assets/icons/, this icon path specification will work:

icon: __dirname + "../assets/icons/icon.png"

In Linux, you can search icon.png in the project directory and change both files(one for Debian and one for Redhat) with your custom icon(with the same name).

If you are using electron-builder, you can follow their documentation on how to add your app-icon.

You can specify a path to set the icon in the electron-builder.json5 configuration file, e.g. for mac:

/*** @see https://www.electron.build/configuration/configuration*/{appId: 'YourAppId',mac: {artifactName: '${productName}_${version}.${ext}',target: ['dmg'],icon: 'public/logo.png',},}

It is recommended to use .ico extension for app icon. You can refer the piece of code which is mentioned below. If suppose you having any other image formats, Just convert it with .ico extension using online converters

let mainWindow;mainWindow = new BrowserWindow({width:1200,height:600,icon: path.join(__dirname,'/icon.ico'),});

• Here _dirname refers to your file path.
• icon.ico - Image file

For windows use Resource Hacker

Download and Install: :D

http://www.angusj.com/resourcehacker/

• Run It
• Select open and select exe file
• On your left open a folder called Icon Group
• Right click 1: 1033
• Click replace icon
• Select the icon of your choice
• Then select replace icon
• Save then close

You should have build the app