TypeError: Cannot read property 'on' of undefined

[ghost]

After

> git clone https://github.com/atom/electron-quick-start
> cd electron-quick-start
> npm install
> npm start

I get error:

> electron-quick-start@1.0.0 start /home/do/dev/electron-quick-start
> electron main.js

App threw an error when running [TypeError: Cannot read property 'on' of undefined]
A JavaScript error occurred in the main process
Uncaught Exception:
TypeError: Cannot read property 'on' of undefined
    at Object.<anonymous> (/home/do/dev/electron-quick-start/main.js:34:4)
    at Module._compile (module.js:425:26)
    at Object.Module._extensions..js (module.js:432:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:313:12)
    at Object.<anonymous> (/home/do/dev/electron-quick-start/node_modules/electron-prebuilt/dist/resources/default_app/main.js:258:23)
    at Module._compile (module.js:425:26)
    at Object.Module._extensions..js (module.js:432:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:313:12)

[vertexportus]

Having the exact same problem..

Tried to use the downloaded .exe, update node, clean cache and re-install electron-prebuilt, and nothing..

I either get an error that module electron can't be found (with require('electron') ) or that app is undefined with require('electron-prebuilt')

[dmr]

I have the same issue here.
Did you resolve the problem by now?

[ghost]

@dmr, no, i switched to nw.js.

[dmr]

The issue is also discussed in the electron main repo:
electron/electron#3708

const electron = require('electron');
const app = require('app');
const BrowserWindow = require('browser-window')

Solved the issue for me :)

[dmr]

Anyone interested in a pull request?
Not sure how stable the new api is.

[ghost]

@dmr, I think that working example better.

[dmr]

I think the issue was/is my computer. I had to manually look for a node_modules/electron folder and delete is. Sorry for the noise.

[jlord]

@chezstov do you have a globally installed electron module?

[ibufu]

@jlord
I installed electron globally.But it still throw the same error.

[dmr]

That is exactly the problem.
"electron" is not the correct package name!

Remove alle the electron installations and install electron-prebuilt, then it works.

[jlord]

That is exactly the problem.
"electron" is not the correct package name!

Yep, @dmr. 👍

If you have a globally installed module called electron (not associated with Electron.js) you'll have a conflict @ibufu. You'll need to remove it and use electron-prebuilt for Electron.js apps.

// cc @chezstov @vertexportus

[jlord]

Going to close this out, hopefully the last response helped others in this thread.

[Pablodotnet]

@dmr I can't make it work with that, can you put here a copy of your main.js? It would be great.

[dmr]

This issue is really old. Removing node_modules and reinstalling will probably fix the issue

[ghost]

Removing node_modules and reinstalling didn't work for me. Any insights?

Here is what I've done:

• Updating node/npm
• Using electron-prebuilt instead of electron
• Made sure electron was not installed globally
• Deleted node_modules and re-ran npm install

Here is the error message:

app.on('ready', createWindow());
   ^


TypeError: Cannot read property 'on' of undefined
    at Object.<anonymous> (/home/harry/web/webcalc/app.js:17:4)
    at Module._compile (module.js:556:32)
    at Object.Module._extensions..js (module.js:565:10)
    at Module.load (module.js:473:32)
    at tryModuleLoad (module.js:432:12)
    at Function.Module._load (module.js:424:3)
    at Module.runMain (module.js:590:10)
    at run (bootstrap_node.js:402:7)
    at startup (bootstrap_node.js:157:9)
    at bootstrap_node.js:521:3

Node version: v7.2.0
NPM version: 4.0.2
Electron version: 1.4.10

System is GNU/Linux running Linux Mint 18 Cinnamon 64 Bit

[davidcoleman007]

Same for me. electron-prebuilt is not a fix. and .on is called on a null object.

[jawatech]

The name "electron-prebuilt" is changed (back?) to "electron" since mid-2016 by the development team.
While you reinstall electron, entries in package.json should be changed accordingly.
(electron-prebuild => electron, and version number , and so on)

[benjaminsuch]

The thing is, although I get this error, it's still working?! createWindow gets executed.

[boredwookie]

One potential cause of this problem can be tied back to executing the electron app from a terminal extension in the Atom editor. This answer on StackOverflow helped me get past the problem: http://stackoverflow.com/a/40664925/1076507. Using a system terminal instead of platformio-ide-terminal plugin inside the Atom editor addressed my problem.

[taoteg]

@boredwookie Thanks you! Made it all the way down here thinking I was borked and then found your working solution. Thank you for saving me many hours of frustrating troubleshooting. This is the issue, not sure what's up with the electron terminal extension not issuing this properly but whatever... small steps. =)

[codekraft-studio]

@boredwookie man you saved me a lot of time i'm so used to that plugin that I didn't think about it

[ivorscott]

@boredwookie Thank you god.

[bluemoehre]

Hitting same problem on MacOS Sierra, Node 8.1.0, VSCode / Terminal / iTerm - doesn't matter. What is causing this?

[alisianoi]

Will second @bluemoehre here: following the quickstart to the letter, getting a Cannot read property 'on' of undefined. My setup is ArchLinux, node is managed by nvm:

nvm --version
0.33.2
node --version
v8.1.0

Also, there is a global electron package installed by the ArchLinux package manager and an local electron in node_modules that I install with npm install electron --save. Removing either global package or wiping the node_modules folder and reinstalling does not fix the issue. My terminal is termite

[alisianoi]

Oh, apologies, my mistake. I did not know that in the line const {app, BrowserWindow} = require('electron') you actually cannot rename app and BrowserWindow to other varible names. That solved my issue.

[searene]

I realized that I included main.js(which is the entry point of electron) in index.html. Removing it worked.

[j-ackerman]

@boredwookie thank you, this solved my issue and likely saved me hours of trial and error

[MggMuggins]

@boredwookie Do you have any idea what causes this? I'd been using Terminal-Fusion (which is a Linux fork of Platformio Term), and had the same problem. Any idea what the cause is?

[gsilvestri]

I'm using VS Code to develop Angular JS application and I have exactly the same problem as VS Code is built on top of Atom.

The problem is that you have the same problem using the debugger tool in VS Code... so: no Atom terminal means no debugger.

Using the Ubuntu terminal instead the Atom/VS Code terminal is a workaround, not a solution: needs to makes electron working with Atom terminal.

[dezryth]

I'm running into this as well with VS Code

[MggMuggins]

Do we think it's an atom bug then, rather than the specific terminal?

[wave100]

@searene Cheers, that's what I did too. Would've taken me forever to figure it out.

[avoitishin]

Missing below step will cause this issue:

Turning this Node application into an Electron application is quite simple - we merely replace the node runtime with the electron runtime.

[tbadalov]

For me using "start": "electron ." script worked. Then just call npm start instead of node index.js

[markobalogh2]

One implication of this issue appears to be that an electron application cannot be launched from a node script via a child_process - has anyone figured out how to do this?

[MggMuggins]

At this point it seems like a rather problematic electron bug. Maybe do some digging and see if you can find out what's causing it. Just happens when running via node API calls? Can you call it using the node runtime but using a lower-level interface (is there a way to use raw syscalls in node)?

[Ynoaparast]

I'm very new to Electron but I figured out the solution to my problem:

I have a very basic Electron application that consists of two files:

• main.js
• index.html

I got the error "Uncaught TypeError: Cannot read property 'on' of undefined", in the dev-tools console, despite my application opening and functioning properly.

My mistake:

I had added a <script src = "path/to/main.js"> in my index.html file, because I wanted an onclick-event to call a function in my main.js Removing this <script> tag removed the error.

[hatton]

With electron 2.0, this is what works in the renderer process:

const { app } = require("electron").remote;

[jdevitt]

The worked for me in VSCode

create .vscode folder in root and create launch.json

{

"version": "0.2.0",
"configurations": [
    {
        "type": "node",
        "request": "launch",
        "name": "Launch Program",
        "program": "${workspaceFolder}\\PATH TO\\YOUR ENTRY POINT.js",
        "stopOnEntry": false,
        "args": [],
        "cwd": "${workspaceFolder}",
        "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron.cmd","runtimeArgs": [
            ".",
            "--enable-logging"
        ],
        "env": {
            
        },
        "console": "internalConsole",
        "sourceMaps": false,
    }
]

}

[svmi3195]

For me this error happened when I, like searene above, occasionally linked main.js in index.html and removing it fixed the problem.

[emmanuel39hanks]

replace your scripts with:
"scripts": {
"test": "electron .",
"start": "electron ."
}

[martynov-oleg]

Я понял, что я включил main.js(который является точкой входа электрона) в index.html. Удаление это сработало.

sanks;)

[krishnappahuded]

In my application it's throwing different error like
TypeError: Cannot set property '_nodeValue' of undefined TypeError: Cannot set property '_nodeValue' of undefined

If we have any solution please help me.

[EduardoSantos7]

In my case the solution appears after check the python-shell official documentation. 'electron' is correct and be sure to pass run function all the parameters that the function needs (following some tutorials, I was not writting arguments: options) also be sure to write correctly PythonShell

const { app, BrowserWindow } = require('electron')

let { PythonShell } = require('python-shell')

PythonShell.run('hello.py', null, function (err, results) {
    if (err) throw err;
    console.log('hello.py finished.');
    console.log('results', results);
});

Hope be useful!

[jabedhossain]

One potential cause of this problem can be tied back to executing the electron app from a terminal extension in the Atom editor. This answer on StackOverflow helped me get past the problem: http://stackoverflow.com/a/40664925/1076507. Using a system terminal instead of platformio-ide-terminal plugin inside the Atom editor addressed my problem.

Apparently this is the case why it was showing an exception in VS Code while debugging. It did run in power-shell terminal but showed exception in VS Code debugger, the solution was to add a configuration file for debugging.

Make sure to uncheck, 'All Exceptions' and 'Uncaught Exceptions' from the debugger window. It should debug smoothly.

[ahmedtahabaqi]

write app in lower case

[levon-isajanyan]

macOS Catalina problem solved by adding into package json "electron ."
{ "name": "universal-local-dev-tools", "version": "xxx", "description": "xxx ", "main": "xxx", "scripts": { "start": "electron .", "test": "electron ." }, "keywords": [ "xxx", "xxx" ], "author": "xxx", "license": "xxx", "dependencies": {}, "devDependencies": { "electron": "xxx" } }

[codedcontainer]

That is exactly the problem.
"electron" is not the correct package name!

Yep, @dmr. 👍

If you have a globally installed module called electron (not associated with Electron.js) you'll have a conflict @ibufu. You'll need to remove it and use electron-prebuilt for Electron.js apps.

// cc @chezstov @vertexportus

1. A package named electrong-prebuild can no longer be found.
2. Installing the latest version in local node_module folder still returns this error.

[codedcontainer]

This issue is really old. Removing node_modules and reinstalling will probably fix the issue

Deleting you local node_modules folder and reinstalling does not fix the problem.

[codedcontainer]

One potential cause of this problem can be tied back to executing the electron app from a terminal extension in the Atom editor. This answer on StackOverflow helped me get past the problem: http://stackoverflow.com/a/40664925/1076507. Using a system terminal instead of platformio-ide-terminal plugin inside the Atom editor addressed my problem.

On Windows tried to use PowerShell and command prompt outside of Visual Studio. Still getting the same error.

[codedcontainer]

If you use the example project you can see that they are calling electron . in their package.json file. If you have your code written in a different location you can rewrite this to something like the below:

"scripts":{
    "start": "electron ./directory/index.js"
}

I wish they were more transparent about this in their documentation.

[pferreirafabricio]

For me using "start": "electron ." script worked. Then just call npm start instead of node index.js

Thank you, this worked for me.