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 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0

Browser: Firefox 128

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

for

6.0M/s

for optimized

5.2M/s

while

4.4M/s

forEach

2.9M/s

for of

1.3M/s

reduce

931K/s

for in

326K/s

View exact numbers

Test name	Executions per second
✓ for	5,963,750 Ops/sec
for optimized	5,198,498 Ops/sec
while	4,406,620 Ops/sec
forEach	2,856,881 Ops/sec
for of	1,272,847 Ops/sec
reduce	931,247 Ops/sec
for in	325,876 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; }