Run results for: for vs for in vs for of vs forEach - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:98.0) Gecko/20100101 Firefox/98.0

Browser: Firefox 98

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
forEach	153035.1 Ops/sec
for of	138914.1 Ops/sec
for in	9347.3 Ops/sec
for	699635.4 Ops/sec

Script Preparation code:

var data = [... new Array(1000)].map((x,i) => i);

Tests:

forEach
let result = 0; data.forEach(x => { result = x; });
for of
let result = 0; for (let x of data) { result = x; }
for in
let result = 0; for (let i in data) { result = data[i]; }
for
let result = 0; for (let i = 0; i < data.length; i++) { result = data[i]; }

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