Run results for: forEach vs for len vs for in vs for of fix

created based off of an archived jsperf benchmark: http://web.archive.org/web/20191008221700/https://jsperf.com/foreach-vs-for-loop-vs-for-in-vs-for-of-vs-babel-for-of change var to let. for of returns the value directly. So you don't get value from testData array.

Go to the benchmark

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:133.0) Gecko/20100101 Firefox/133.0

Browser: Firefox 133

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

for

17.1M/s

for optimized

17.0M/s

while

11.9M/s

forEach

6.5M/s

for of

1.8M/s

reduce

1.6M/s

for in

674K/s

View exact numbers

Test name	Executions per second
✓ for	17,063,844 Ops/sec
for optimized	17,013,754 Ops/sec
while	11,921,378 Ops/sec
forEach	6,479,226 Ops/sec
for of	1,801,709 Ops/sec
reduce	1,589,660 Ops/sec
for in	673,785 Ops/sec

HTML Preparation code:

<script>
    Benchmark.prototype.setup = function() {
        var testData = [];
        for (var i = 0; i < 100; i++) {
            testData.push(i);
        }
    };
</script>

Tests:

forEach
let res = 0; testData.forEach(function(x) { res += x; });
for
let res = 0; for (let i = 0; i < testData.length; i++) { res += testData[i]; }
for optimized
let res = 0; for (let i = 0, len = testData.length; i < len; i++) { res += testData[i]; }
reduce
var res = testData.reduce(function(sum, x) { return sum + x; }, 0);
while
var res = 0; var i = testData.length; while (i--) { res += testData[i]; }
for in
var res = 0; for (let data in testData) { res += testData[data]; }
for of
var res = 0; for (var data of testData) { res += data; }