Run results for: FlatMap method vs for loop

Run details:

User agent: Mozilla/5.0 (iPad; CPU OS 18_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/133.0.6943.84 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 133

Operating system: iOS 18.3.1

Device Platform: Tablet

Date tested: one year ago

for loop

54K/s

flatMap

5K/s

View exact numbers

Test name	Executions per second
✓ for loop	54,436 Ops/sec
flatMap	5,332 Ops/sec

Script Preparation code:

var arr = Array(10_000).fill(0);

Tests:

flatMap
arr.flatMap(x => [x, x * 2]);
for loop
const n = arr.length; const acc = new Array(n * 2); for (let i = 0; i < n; i++){ const x = arr[i]; acc[i * 2] = x; acc[i * 2 + 1] = x * 2; }