Run results for: fill then map (with null/undefined/""/0) vs for loop 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/120.0.0.0 Safari/537.36

Browser: Chrome 120

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

For loop

3.5M/s

.fill(0).map()

1.2M/s

.fill(true).map()

1.1M/s

.fill("").map()

1.1M/s

.fill(undefined).map()

1.1M/s

.fill(null).map()

1.1M/s

Array.from().map()

126K/s

Array.from() only

120K/s

View exact numbers

Test name	Executions per second
✓ For loop	3,496,883 Ops/sec
.fill(0).map()	1,174,947 Ops/sec
.fill(true).map()	1,127,920 Ops/sec
.fill("").map()	1,114,922 Ops/sec
.fill(undefined).map()	1,114,301 Ops/sec
.fill(null).map()	1,074,071 Ops/sec
Array.from().map()	126,393 Ops/sec
Array.from() only	120,050 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);
.fill(0).map()
Array(100).fill(0).map((_, i) => i+i);
For loop
const a = new Array(100) for(let i = 0; i < a.lenght; i++) a[i] = i+i