Run results for: Lazy test vs call

Run details:

User agent: Mozilla/5.0 (Linux; Android 6.0.1; MIX Build/MXB48T) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.91 Mobile Safari/537.36

Browser: Chrome Mobile 55

Operating system: Android 6.0.1

Device Platform: MIX

Date tested: 7 years ago

Test name	Executions per second
Lazy with existence test	841.9 Ops/sec
Lazy with fetch call	902.3 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