gistfile1.txt

/*
on my machine:
es3 50000095000000 1085 ms
es5 50000095000000 11037 ms
es6 50000095000000 910 ms
es3 50000095000000 1100 ms
es5 50000095000000 11640 ms
es6 50000095000000 876 ms
*/

function outer3() {
  var sum = 0;

  var t0 = Date.now();
  for (var i = 0; i < 10000000; i++) {
    var f = (function(_this) {
      return (function(x) {
        return x + _this;
      });
    })(this);
    sum += f(i);
  }

  var t1 = Date.now();
  console.log("es3", sum, t1 - t0, "ms");
}

function outer5() {
  var sum = 0;

  var t0 = Date.now();
  for (var i = 0; i < 10000000; i++) {
    var f = (function(x) { return x + this; }).bind(this);
    sum += f(i);
  }

  var t1 = Date.now();
  console.log("es5", sum, t1 - t0, "ms");
}

function outer6() {
  var sum = 0;
  
  var t0 = Date.now();
  for (var i = 0; i < 10000000; i++) {
    var f = (x) => { return x + this };
    sum += f(i);
  }
  
  var t1 = Date.now();
  console.log("es6", sum, t1 - t0, "ms");
}

outer3.bind(10)()
outer5.bind(10)()
outer6.bind(10)()

outer3.bind(10)()
outer5.bind(10)()
outer6.bind(10)()