electron/docs/fiddles/system/protocol-handler/launch-app-from-URL-in-another-app/renderer.js

// This file is required by the index.html file and will
// be executed in the renderer process for that window.
// All APIs exposed by the context bridge are available here.

// Binds the buttons to the context bridge API.
document.getElementById('open-in-browser').addEventListener('click', () => {
  shell.open();
});