Run results for: flatmap vs for of vs custom flatMap (version 2)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.4 Safari/605.1.15

Browser: Safari 16

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
flatmap	94852.6 Ops/sec
for of	214357.7 Ops/sec
custom flatMap	27077.8 Ops/sec

Script Preparation code:

var n = 1000
var arr = [...Array(n)];

function flatMap(arr, fn) {
  const acc = [];
  for (let i = 0; i < arr.length; i++) {
    acc.push(...fn(arr[i]));
  }
  return acc;
}
var fn = (x,i) => [i + 1, i + 2]

Tests:

flatmap
arr.flatMap(fn)
for of
let res = [], i=0; for(const i of arr) res.push(...[i + 1, i + 2]);
custom flatMap
flatMap(arr, fn)