How to debug node js spawn ENOENT error.js

// paste this before your require child_process at the beginning of your main index file.
(function() {
  var childProcess = require("child_process");
  var oldSpawn = childProcess.spawn;
  function mySpawn() {
      console.log('spawn called');
      console.log(arguments);
      var result = oldSpawn.apply(this, arguments);
      return result;
  }
  childProcess.spawn = mySpawn;
})();