Run details:
Mozilla/5.0 (iPhone; CPU iPhone OS 15_4_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.4 Mobile/15E148 Safari/604.1
Mobile Safari 15
iOS 15.4.1
Mobile
2 years ago
Test name Executions per second
for let 604.2 Ops/sec
for var 603.6 Ops/sec
for let cached 779.6 Ops/sec
for let cached (const) 818.5 Ops/sec
for var cached 790.5 Ops/sec
forEach 1101.9 Ops/sec
Script Preparation code:
x
 
var array = [];
for (var i=0, t=10000; i<t; i++) {
    array.push(Math.round(Math.random() * t))
}
var t=0;
Tests:
  • for let

     
    for (let i = 0; i < array.length; i++) {
      t += array[i];
    }
  • for var

     
    for (var i = 0; i < array.length; i++) {
      t += array[i];
    }
  • for let cached

     
    let len=array.length;
    for (let i = 0; i < len; i++) {
      t += array[i];
    }
  • for let cached (const)

     
    const len=array.length;
    for (let i = 0; i < len; i++) {
      t += array[i];
    }
  • for var cached

     
    var len=array.length;
    for (var i = 0; i < len; i++) {
      t += array[i];
    }
  • forEach

     
    array.forEach(function(v, i) {
      t += v;
    });