How to use FS module inside Electron.Atom\WebPack application?

In addition to the accepted answer.

If you are using Webpack (like when you are using Angular, React or other frameworks) require will be resolved by webpack, which will screw it's usage at runtime.

Use window.require instead.

Ex:

var remote = window.require('electron').remote;
var electronFs = remote.require('fs');
var electronDialog = remote.dialog;

Note: There is no need to use remote in order to access any of Node API from a renderer process as it's fully exposed.

const fs = window.require('fs');
const path = window.require('path');

will do.

Update

Starting from v5 of Electron, the Node API is no longer exposed by default in the renderer process!

The default for the nodeIntegration flag changed from true to false.

You can enable it when creating the Browser Window:

app.on('ready', () => {
    mainWindow = new BrowserWindow({
        webPreferences: {
            nodeIntegration: true, // <--- flag
            nodeIntegrationInWorker: true // <---  for web workers
        }
    });
});

The security risk of activating nodeIntegration

nodeIntegration: true is a security risk only when you're executing some untrusted remote code in your application. For example, suppose your application opens up a third party webpage. That would be a security risk because the third party webpage will have access to node runtime and can run some malicious code on your user's filesystem. In that case it makes sense to set nodeIntegration: false. If your app is not displaying any remote content, or is displaying only trusted content, then setting nodeIntegration: true is okay.

And finally, the recommended secure way from the doc:

https://electronjs.org/docs/tutorial/security#2-do-not-enable-nodejs-integration-for-remote-content

Problem is solved.

Need use in electron app (where you add the bundle):

var remote = require('electron').remote;
var electronFs = remote.require('fs');
var electronDialog = remote.dialog;