How to execute locally installed Node.js application by child_process.spawn()?

Question

I want to execute the Electron application by child_process.spawn:

import ChildProcess, {ChildProcess as ChildProcess__type} from 'child_process';
const childProcess: ChildProcess__type = ChildProcess.spawn(
        'electron',
        ['ProjectInitializer__ElectronMain.js'],
        { cwd: __dirname } // current project root
    );

I got Error: spawn electron ENOENT error. Electron has been installed locally, AFAIK is the good practice. Also, electron ProjectInitializer__ElectronMain.js works, it to execute this console command from my project directory.

Following frequently up-voted ENOENT error debugging guidance, I got the cause: there is no directory among process.env.PATH, which includes electron.

I know about PATH variable not much, so I can not answer what must be in this variable and what is not. But what I want to ask is: how to execute locally installed (in node_modules) Node.js applications (like electron)?

By the way, execa which is known as improved child_process runs electron without errors (update: version 2.x.x already do not runs):

import executeExternalCommand, { ExecaReturnValue } from 'execa';

try {
  await executeExternalCommand(
      'electron',
      ['ProjectInitializer__ElectronMain.js'],
      { cwd: __dirname }
  );
} catch (error) {
  console.error(error);
}

Somehow, thanks to { cwd: __dirname }, the execa v 1.x.x knows, where should to find the electron. Unfortunately, execa has too small community and small documentations, so stopped to use it.

Additional information

How I run this Node.js script which has the spawn parameter

By command my-library init which I created.

In package.json:

"bin": {
  "my-library": "bin/my-library"
}

In bin/my-library (no filename extension):

#!/usr/bin/env node

require('../CLI').interpretConsoleCommandAndExecute(process.argv);

In CLI.js I parse the console command, and if it is the my-library init, I'll try to execute

const childProcess: ChildProcess__type = ChildProcess.spawn(
   'electron',
   [ 'ProjectInitializer__ElectronMain.js' ],
   { cwd: __dirname }
);

console.log(process.env) output

Below output is for PhpStorm build-in console, however in other consoles, e. g. in cmder, output is different.

{ FPS_BROWSER_APP_PROFILE_STRING: 'Internet Explorer',
  CommonProgramFiles: 'C:\\Program Files\\Common Files',
  PROMPT: '$P$G',
  SESSIONNAME: 'Console',
  COMPUTERNAME: 'MSI',
  OneDriveConsumer: 'D:\\OneDrive',
  __INTELLIJ_COMMAND_HISTFILE__:
   'C:\\Users\\i\\.PhpStorm2019.1\\config\\terminal\\history\\history-34',
  SystemDrive: 'C:',
  NUMBER_OF_PROCESSORS: '12',
  LOGONSERVER: '\\\\MSI',
  TEMP: 'C:\\Users\\i\\AppData\\Local\\Temp',
  TMP: 'C:\\Users\\i\\AppData\\Local\\Temp',
  HOMEPATH: '\\Users\\i',
  PATHEXT: '.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JSE;.WSF;.WSH;.MSC',
  USERNAME: 'i',
  ProgramFiles: 'C:\\Program Files',
  USERDOMAIN_ROAMINGPROFILE: 'MSI',
  LOCALAPPDATA: 'C:\\Users\\i\\AppData\\Local',
  TERMINAL_EMULATOR: 'JetBrains-JediTerm',
  PROCESSOR_IDENTIFIER: 'Intel64 Family 6 Model 158 Stepping 10, GenuineIntel',
  DriverData: 'C:\\Windows\\System32\\Drivers\\DriverData',
  APPDATA: 'C:\\Users\\i\\AppData\\Roaming',
  ALLUSERSPROFILE: 'C:\\ProgramData',
  USERDOMAIN: 'MSI',
  OS: 'Windows_NT',
  PROCESSOR_LEVEL: '6',
  ProgramData: 'C:\\ProgramData',
  ComSpec: 'C:\\Windows\\system32\\cmd.exe',
  PROCESSOR_ARCHITECTURE: 'AMD64',
  FPS_BROWSER_USER_PROFILE_STRING: 'Default',
  SystemRoot: 'C:\\Windows',
  PROCESSOR_REVISION: '9e0a',
  OneDrive: 'D:\\OneDrive',
  PSModulePath:
   'C:\\Program Files\\WindowsPowerShell\\Modules;C:\\Windows\\system32\\WindowsPowerShell\\v1.0\\Modules',
  PATH:
   'D:\\PhpStorm\\InHouseDevelopment\\my-library\\node_modules\\.bin;C:\\ProgramData\\DockerDesktop\\version-bin;C:\\Program Files\\Docker\\Docker\\Resources\\bin;C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\iCLS\\;C:\\Program Files
\\Intel\\Intel(R) Management Engine Components\\iCLS\\;C:\\Windows\\system32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\;C:\\Windows\\System32\\OpenSSH\\;C:\\Program Files (x86)\\NVIDIA Corporation\\PhysX\\Common;C:\\Pro
gram Files\\Intel\\WiFi\\bin\\;C:\\Program Files\\Common Files\\Intel\\WirelessCommon\\;C:\\Program Files (x86)\\Intel\\Intel(R) Management Engine Components\\DAL;C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\DAL;C:\\Program Files (x86)\\Intel\\I
ntel(R) Management Engine Components\\IPT;C:\\Program Files\\Intel\\Intel(R) Management Engine Components\\IPT;C:\\Program Files (x86)\\Common Files\\Acronis\\VirtualFile\\;C:\\Program Files (x86)\\Common Files\\Acronis\\VirtualFile64\\;C:\\Program Files (x86)\\Com
mon Files\\Acronis\\FileProtector\\;C:\\Program Files (x86)\\Common Files\\Acronis\\FileProtector64\\;C:\\Program Files (x86)\\Common Files\\Acronis\\SnapAPI\\;C:\\Program Files\\nodejs\\;C:\\Program Files\\Git\\cmd;C:\\Program Files (x86)\\Yarn\\bin\\;C:\\Users\\t
okug\\AppData\\Local\\Microsoft\\WindowsApps;C:\\Users\\i\\AppData\\Roaming\\npm;C:\\Users\\i\\AppData\\Local\\Yarn\\bin;C:\\texlive\\2019\\bin\\win32',
  'ProgramFiles(x86)': 'C:\\Program Files (x86)',
  USERPROFILE: 'C:\\Users\\i',
  windir: 'C:\\Windows',
  ProgramW6432: 'C:\\Program Files',
  configsetroot: 'C:\\Windows\\ConfigSetRoot',
  'CommonProgramFiles(x86)': 'C:\\Program Files (x86)\\Common Files',
  PUBLIC: 'C:\\Users\\Public',
  HOMEDRIVE: 'C:',
  CommonProgramW6432: 'C:\\Program Files\\Common Files' }

Trying to execute ChildProcess.spawn('env')

In Php Strorm console, it causes familiar Error: spawn env ENOENT.

@TarunLalwani, The console command `electron ProjectInitializer__ElectronMain.js` in my project directory will start application correctly. — Takeshi Tokugawa YD, Jun 26 '19 at 08:41
Can you add `console.log(process.env)` at top of your file and also instead of running `electron` run the `env` command with no parameters and see if there is a difference. Also, want to know how you running this node js script which has the spawn parameter — Tarun Lalwani, Jun 26 '19 at 08:57
@TarunLalwani, thank you for the help. I added this information in question field. — Takeshi Tokugawa YD, Jun 26 '19 at 09:14
Also, try using `const childProcess: ChildProcess__type = ChildProcess.spawn( 'electron', [ 'ProjectInitializer__ElectronMain.js' ], { cwd: __dirname, env: process.env } );` — Tarun Lalwani, Jun 26 '19 at 09:25
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/195565/discussion-between-tarun-lalwani-and-gurebu-bokofu). — Tarun Lalwani, Jun 26 '19 at 09:38

score 1 · Accepted Answer · answered Jun 29 '19 at 15:34

As discussed in the chat, the error you are getting is usually caused by the fact that the executable you are trying to run is not available

Now there are multiple reasons the executable may not be available

The executable is not there at all anywhere on the system
The executable is there but not in the folders defined by system's PATH variable
The executable is there in the current directory but the directory context in which the process is being run is different

To fix #1 and #2 you just install the executable globally in system PATH

For fixing #3 you can do two things. Add the path for the current directory ({ cwd: __dirname}) and also a relative path to executable

const childProcess: ChildProcess__type = ChildProcess.spawn( 
Path.resolve(__dirname, 'node_modules/.bin/electron'), 
[ Path.resolve(__dirname, 'ProjectInitializer__ElectronMain.js') ], 
{ cwd: __dirname} 
);

or

const childProcess: ChildProcess__type = ChildProcess.spawn( 
'./node_modules/.bin/electron'), 
[ Path.resolve(__dirname, 'ProjectInitializer__ElectronMain.js') ], 
{ cwd: __dirname} 
);

or

const childProcess: ChildProcess__type = ChildProcess.spawn( 
'node_modules/.bin/electron', 
[ './ProjectInitializer__ElectronMain.js' ], 
{ cwd: __dirname} 
);

In case you decide to override the PATH environment variable you can do it passing the env parameters with more values

const childProcess: ChildProcess__type = ChildProcess.spawn( 
'node_modules/.bin/electron', 
[ './ProjectInitializer__ElectronMain.js' ], 
{ cwd: __dirname, env: {....}} 
);

You can use the existing environment variables from process.env and then update the same, and pass it to env parameter

O'K, I solved my problem as in first listing! Thank you for your time. Vote-up and reputation prize for you. — Takeshi Tokugawa YD, Jul 01 '19 at 07:16

Maus · Answer 2 · 2019-06-27T17:19:00.743

it’s likely that you need to specify the full path to the electron command, since it isn’t on your path.

If you are running your script from your project root, electron is probably at in ./node_modules/.bin/electron, if they packaged up the app to be run that way.

I would guess that your alternative library checks node_modules by default.

The alternative would be to ensure electron is in your path, but that requires updating your system configuration, which it would be weird for a library to do.

Edit: example of call with path:

const childProcess: ChildProcess__type = ChildProcess.spawn(
   'node_modules/.bin/electron',
   [ 'ProjectInitializer__ElectronMain.js' ],
   { cwd: __dirname }
);

I'd also add some dumb logging on the process, so you know why the process failed:

function log(data) {
    console.log("" + data)
}
child_process.stdout.on('data', log)
child_process.stderr.on('data', log)
child_process.on('close', log)

Thank you for the answer. You totally right about "electron is probably at in `./node_modules/.bin/electron` and "which it would be weird for a library to do.". However, I did not understand the solution. Is it possible to specify the path to electron inside `ChildProcess.spawn` invocatioin()? (`{ cwd: __dirname }`) does not do it. — Takeshi Tokugawa YD, Jun 27 '19 at 05:27

How to execute locally installed Node.js application by child_process.spawn()?

Additional information

2 Answers2

Edit: example of call with path:

Linked