Run results for: JS loops comparison

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser: Chrome 122

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

.forEach

50K/s

iterator loop

42K/s

.map

35K/s

indexed loop

2K/s

View exact numbers

Script Preparation code:

var data = [...Array(10000).keys()]

Tests:

.map
const result = data.map(x => x + 1)
iterator loop
const result = []; for (const val of data) { result.push(val + 1); }
indexed loop (assign)
const result = new Array(data.length); for (let i = 0; i < data.length; i++) { result[i] = data[i] + 1; }
.forEach (assign)
const result = new Array(data.length); data.forEach((value, i) => result[i] = value + 1);
indexed loop (push)
const result = []; for (let i = 0; i < data.length; i++) { result.push(data[i] + 1); }
.forEach (push)
const result = []; data.forEach((value, i) => result.push(value + 1));