Run results for: "this" dereference

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36

Browser: Chrome 57

Operating system: Windows

Device Platform: Other

Date tested: 7 years ago

Test name	Executions per second
Using "this"	10135.1 Ops/sec
Using local vars	9837.6 Ops/sec

Script Preparation code:

function Foo() {
  this.data = [];
  for (var i = 0; i < 1e5; ++i) {
    this.data[i] = Math.pow(Math.random(), Math.random());
  }
}
Foo.prototype.test1 = function() {
  var sum = 0;
  for (var i = 0; i < this.data.length; ++i) {
    sum += this.data[i];
  }
  return sum;
}
Foo.prototype.test2 = function() {
  var sum = 0;
  var data = this.data;
  for (var i = 0, ilen = this.data.length; i < ilen; ++i) {
    sum += data[i];
  }
  return sum;
}
  
var foo = new Foo();

Tests:

Using "this"
foo.test1();
Using local vars
foo.test2();

Run results for: "this" dereference

Using "this"

Using local vars