Run results for: Lazy test vs call

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0

Browser: Firefox 46

Operating system: Windows

Device Platform: Other

Date tested: 7 years ago

Test name	Executions per second
Lazy with existence test	88118.4 Ops/sec
Lazy with fetch call	89472.1 Ops/sec

Script Preparation code:

function mkLazyTest(fn) {
  var thunk = fn, ran = false, value = null;
  return function() {
    if (!ran) {
      value = thunk();
      ran = true;
    }
    return value;
  };
}

function mkLazyCall(fn) {
  var thunk = fn;
  var get = function() {
    var value = thunk();
    get = function() { return value; };
    return value;
  };
  return function() { return get(); };
}

function cfn(v) { 
  return function() { return v; }
}

var fn = cfn(1);
var lz1 = mkLazyTest(fn);
var lz2 = mkLazyCall(fn);
var i = 0, iterations = 1000;

Tests:

Lazy with existence test
for (i = 0; i < iterations ; i++) { lz1(); }
Lazy with fetch call
for (i = 0; i < iterations ; i++) { lz2(); }

Run results for: Lazy test vs call

Tests if a lazy implementation that uses a test vs one that replaces the thunk function is more efficient

Lazy with existence test

Lazy with fetch call