Electron Cannot find module /resources/app/index.js

I'm new to electron and have made my first electron application, it runs normally running npm start but when using npm run I am unable to execute my application. (I am running ubuntu linux) The cli gives this error message when running the executable file:

A JavaScript error occurred in the main process
Uncaught Exception:
Error: Cannot find module '/home/user/Documents/dev/cocoa/cocoa-linux-x64/resources/app/index.js'
    at Module._resolveFilename (module.js:455:15)
    at Function.Module._resolveFilename (/home/user/Documents/dev/cocoa/cocoa-linux-x64/resources/electron.asar/common/reset-search-paths.js:35:12)
    at Function.Module._load (module.js:403:25)
    at Object.<anonymous> (/home/user/Documents/dev/cocoa/cocoa-linux-x64/resources/electron.asar/browser/init.js:171:8)
    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)

This is my package.json :

{
  "name": "cocoa",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "start": "electron main.js",
    "package-linux" : "electron-packager . --platform=linux --arch=x64 --electron-version=1.4.13"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "electron-packager": "^8.7.1"
  }
}

this is the main.js file :

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

app.on('ready', ()=> {
  let win = new BrowserWindow({
    width:400,
    height:400
  })
  win.loadURL('http://google.com')
})

Does anyone know what I am doing wrong, thank you for your help.