Run results for: fill then map (with null/undefined/"") vs array.from - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 121

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

.fill("").map()

1.6M/s

.fill(null).map()

1.6M/s

.fill(undefined).map()

1.5M/s

.fill(true).map()

1.4M/s

Array.from().map()

218K/s

Array.from() only

191K/s

View exact numbers

Test name	Executions per second
✓ .fill("").map()	1,631,869 Ops/sec
.fill(null).map()	1,556,310 Ops/sec
.fill(undefined).map()	1,508,456 Ops/sec
.fill(true).map()	1,434,345 Ops/sec
Array.from().map()	217,909 Ops/sec
Array.from() only	191,480 Ops/sec

Tests:

Array.from() only
Array.from({ length: 100 }, (_, i) => i+i);
Array.from().map()
Array.from({ length: 100 }).map((_, i) => i+i);
.fill("").map()
Array(100).fill("").map((_, i) => i+i);
.fill(null).map()
Array(100).fill(null).map((_, i) => i+i);
.fill(undefined).map()
Array(100).fill(null).map((_, i) => i+i);
.fill(true).map()
Array(100).fill(true).map((_, i) => i+i);