Run results for: Array.from with mapper vs Array.fill

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 132

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

fill twice

2K/s

from with mapper

43/s

View exact numbers

Test name	Executions per second
✓ fill twice	1,710 Ops/sec
from with mapper	43 Ops/sec

Tests:

from with mapper
let n = 10000, length = 50 const result = [] const lengthObj = {length:length} const mapper = (_, i) => i < 25 ? 0 : 1 for (let i = 0; i < n; ++i) { result.push(Array.from(lengthObj, mapper)); }
fill twice
let n = 10000, length = 50 const result = [] for (let i = 0; i < n; ++i) { result.push(Array(5).fill(0, 0, 25).fill(1, 25)); }