Benchmark: FlatMap vs concatenation

Script Preparation code:

var arr = Array(10_000).fill({ items: ['item1', 'item2', 'item3']});

Tests:

flatMap
const arr_1 = arr.flatMap(x => x.items);
concatenation
const arr_2 = []; arr.forEach(el => { arr_2.push(...el.items) })
concatenation with for of loop
const arr_3 = []; for (let el of arr) { arr_3.push(...el.items) }
concatenation with for loop
const arr_4 = []; const n = arr.length; for (var i = 0; i < n; i++) { arr_4.push(...arr[i].items) }

Rendered benchmark preparation results:

Previous results

Test case name	Result
flatMap
concatenation
concatenation with for of loop
concatenation with for loop

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Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.46.742.918 Safari/537.36

Browser/OS: Chrome 112 on Windows

Test name	Executions per second
flatMap	90.4 Ops/sec
concatenation	1801.7 Ops/sec
concatenation with for of loop	2153.9 Ops/sec
concatenation with for loop	531.2 Ops/sec

FlatMap vs concatenation (version: 0)