Performance of Function.prototype.call

test.js

function test(f) {
  var counter = 10000000;
  performance.clearMarks();
  performance.mark('StartTest');
  for(var i = counter; i > 0; --i) {
    f();
  }
  performance.mark('EndTest');
  var marks = performance.getEntriesByType('mark');
  return marks[1].startTime-marks[0].startTime;
}

function testFunc() {
  return this.x * this.x;
}

function add(a,b) { return a+b; }

function sum(ns) { return ns.reduce(add,0); }

function avg(ns) { return sum(ns)/ns.length; }

function report(run) { console.log(run.description, ':', avg(run), 'ms') }

function Foo(x) { this.x = x; }

Foo.prototype.test = testFunc;

var obj1 = new Foo(10);

var obj2 = { x: 10 };

function testRun(f) {
  var runs = [];
  for(var i = 0; i < 10; i++) {
    runs.push(test(f));
  }
  return runs;
}

testRun(() => obj1.test()); // if i don't do this, the tests are elided or something

var runs = [
  ()=> obj1.test(),
  ()=> obj1.test.call(obj1),
  ()=> testFunc.call(obj1),
  ()=> testFunc.call(obj2),
  ()=> obj1.test.call(obj2),
  ()=> obj1.test.call({x:10}),
  ()=> testFunc.call({x:10})
].map(t => {
  var run = testRun(t);
  run.description = t.toString();
  return run;
});
runs.forEach(report);