To compile donsol-js as an Electron app (in Windows):
1) Download and extract this ZIP: https://github.com/neauoire/donsol-js/archive/master.zip
2) Install Node.js: https://nodejs.org/
3) Open Command Prompt, and navigate (using the cd command) into the donsol-js-master folder you extracted.
4) Type: npm install electron-packager into the same Command Prompt window, and hit ENTER to install electron-packager.
5) Type: npm run build_win into the same Command Prompt window, and hit ENTER to build the Electron app.
6) In the donsol-js-master folder, there will be a new folder named ~ . In File Explorer, click through all the sub-directories (for me it was ~ , then Desktop, and finally Donsol-win32-x64), and at the end you'll find the file Donsol.exe, which when you open it, should run the game!
Note: Although I haven't tested it, the commands npm run build_osx and npm run build_linux should be the scripts you would use instead of npm run build_win (to build it on macOS and Linux respectively).