On: How necessary are var, let, and const?

[shawndumas]

To be fair; getting the benefit of const would require code too though:

  function constUseful () {
    var guarded = 1;

    (function loop (orgGuarded) {
      setTimeout(function () {
        if (guarded !== orgGuarded) {
          throw 'guarded reassigned!';
        }
        loop(orgGuarded);
      }, 0);
    })(guarded);

    guarded = 2;
  }

  constUseful();

That's an approximation of const's value as delineated in code.