Run results for: compare the ways to generate a random array for iteration + while

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36

Browser: Chrome 145

Operating system: Linux

Device Platform: Desktop

Date tested: 4 months ago

Array(n).fill(null)

109K/s

[...Array(n)]

108K/s

while(up--) myArray.push(Math.random());

60K/s

Array.from({ length: n })

21K/s

Array.from({ length:n }, (item, i) => i)

20K/s

View exact numbers

Test name	Executions per second
✓ Array(n).fill(null)	108,739 Ops/sec
[...Array(n)]	107,696 Ops/sec
while(up--) myArray.push(Math.random());	60,162 Ops/sec
Array.from({ length: n })	20,517 Ops/sec
Array.from({ length:n }, (item, i) => i)	20,048 Ops/sec

Tests:

[...Array(n)]
[...Array(1000)].map(() => Math.random());
Array(n).fill(null)
Array(1000).fill(null).map(() => Math.random());
Array.from({ length: n })
Array.from({ length: 1000 }).map(() => Math.random());
Array.from({ length:n }, (item, i) => i)
Array.from({ length:1000 }, () => Math.random());
while(up--) myArray.push(Math.random());
let myArray = []; let up = 1000; while(up--) myArray.push(Math.random());