gaslight.js

// Gaslighting With Javascript

(function () {
  var obj = {
    fn : function () {}
  , num: 1
  , obj: {}
  , str: 'Hello, world!'
  };

  console.log(typeof obj.f‌n),  // undefined
  console.log(typeof obj.nu‌m); // undefined
  console.log(typeof obj.o‌bj); // undefined
  console.log(typeof obj.st‌r); // undefined
  console.log(typeof ob‌j);     // undefined
  return obj;
})();

Haha, it's confusing a little bit ))
There is invisible (inside of console.log) character: "< 200c >" // withoyt white spaces ))

console.log(typeof ob< 200c >j);