How necessary are var, let, and const?(raganwald.com)

    function f() {
      const queue = [];
      consumer(queue);
      return queue;
    }

    function silly(x, y, z, args) {
      args = Array.prototype.slice.call(arguments);
      args.shift();
      args.shift();
      args.shift();
      args.shift();
      x = y = z = undefined;

      // regular function goes here
    }

  function constUseful () {
    var guarded = 1;

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

    guarded = 2;
  }

  constUseful();