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TypeError: Cannot read properties of undefined (reading 'members')

See original GitHub issue

Issue Description

So I’m new to electron, but not to NPM and certainly not to JavaScript. Initially when I was getting errors they were things like “require” is not defined. I read through the issues and updated this like so:


const createWindow = () => {
    const win = new BrowserWindow({
        width: 800,
        height: 600,
        titleBarStyle: "hidden",
        webPreferences: {
            preload: path.join(__dirname, 'preload.js'),
            enableRemoteModule: true // <-- as you can see I do have this already.

    ipcMain.handle('dark-mode:toggle', () => {
        if (nativeTheme.shouldUseDarkColors) {
          nativeTheme.themeSource = 'light'
        } else {
          nativeTheme.themeSource = 'dark'
        return nativeTheme.shouldUseDarkColors

    ipcMain.handle('dark-mode:system', () => {
        nativeTheme.themeSource = 'system'


I have the code in my preload script, after I removed it from my render script where it also wasn’t working. Here is the important sections of my preload.js

const customTitlebar = require('custom-electron-titlebar');

window.addEventListener('DOMContentLoaded', () => {

    let MyTitleBar = new customTitlebar.Titlebar({
        backgroundColor: customTitlebar.Color.fromHex('#ffffff')

    const replaceText = (selector, text) => {
        const element = document.getElementById(selector)
        if (element) element.innerText = text
      for (const dependency of ['chrome', 'node', 'electron']) {
        replaceText(`${dependency}-version`, process.versions[dependency])

The actual behavior is as follows:

  1. I use npm run start
  2. The app opens, completely white, then loads content after about 20 seconds with no titlebar present.
  3. Then I open developer tools and it gives me the error that is the title for this issue with lots of things having to do with remote.js, and a lot of yellow errors like DevTools failed to load source map: Could not parse content, Unexpected end of JSON input. It always points to files with formats following “foo”

Expected behavior I would expect a titlebar and a working app

Desktop (please complete the following information):

  • OS: Windows 11 Home 21H2
  • Electron 16.0.7
  • Node Version: v14.18.1

Issue Analytics

  • State:closed
  • Created a year ago
  • Comments:12 (2 by maintainers)

github_iconTop GitHub Comments

ShivamRawat0lcommented, Jan 24, 2022

@AlexTorresSk It is now working for me fine. Just run the code in the preload.js and every thing should work fine. I was trying to run it inside the react js without proper params.

ShivamRawat0lcommented, Jan 22, 2022

Lol. Just getting this same error. Is it due to the version ? @mcnamara-charles

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