electron: Can't run command line tool using child_process after packaged

• Electron version: 1.4.4
• Operating system: OSX 10.11.6

The user scenario is like this:

1. user selects a directory
2. use node’s child_process to run npm install under this directory

The code snippets related to running command line is: (ES6)

import cp from 'child_process';
import { ipcRenderer } from 'electron';

export function runCommand(command, option, done) {
  const child = cp.exec(command, option);
  ipcRenderer.sendSync('newChildProcess', child.pid);
  done({
    type: 'id',
    data: child.pid
  });
  child.stdout.on('data', (data) => {
    done({
      type: 'stdout',
      data
    });
  });
  child.stderr.on('data', (data) => {
    done({
      type: 'stdout',
      data
    });
  });
  child.on('close', (code) => {
    done({
      type: 'close',
      data: code
    });
  });
}

In development phase, it works well. But after I package the code as dmg on Mac, the exec throw a “/bin/sh: npm command not found” error with an exit code 127. I’m sure I have installed npm on my machine.

Is there anyone know how to fix this?