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

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36 Edg/121.0.0.0

Browser: Chrome 121

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

.fill("").map()

1.2M/s

.fill(null).map()

1.2M/s

.fill(undefined).map()

1.2M/s

.fill(true).map()

1.1M/s

Array.from().map()

169K/s

Array.from() only

160K/s

View exact numbers

Test name	Executions per second
✓ .fill("").map()	1,226,426 Ops/sec
.fill(null).map()	1,186,502 Ops/sec
.fill(undefined).map()	1,173,318 Ops/sec
.fill(true).map()	1,103,153 Ops/sec
Array.from().map()	169,267 Ops/sec
Array.from() only	160,199 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);