Add use case / motivation / explanation to readme

[vjpr]

Why is this needed instead of just using child_process('electron', {stdio: 'pipe'}).on('data', () => {})?

I assume its because child.send wouldn't work.

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From initial glance I thought you were overriding some require('electron') stuff, but the Electron class is just a wrapper.

Looks like it just overrides console in the renderer (preload.js) to send those messages to the main process (runner.js), which then sends them back to the node script via stdio: ipc process.send.

[juliangruber]

This module lets you feed JS to a hidden browser, and returns the browser's console output. The difference to your example is that it doesn't execute it in the main process, but in the renderer process, where you have access to the DOM and all browser JS APIs. Does that answer your question?