Benchmark: compare the ways to generate an array filled with empty objects for iteration

compare the ways to generate an array filled with empty objects for iteration (version: 1)

- Array.push - Array.apply: Array.apply(null, Array(100)) - Destructuring operator: [...Array(100)] - Array.prototype.fill Array(100).fill(undefined) - Array.from Array.from({ length: 100 })

Comparing performance of: `Array.apply(null, Array(n)) vs [...Array(n)] vs Array(n).fill(null) vs Array.from({ length: n }) vs Array.from({ length:n }, (item, i) => i) vs Array.push vs Array with length + push`

Created: one year ago by: Guest

Go to the latest result

Tests:

Array.apply(null, Array(n))
Array.apply(null, Array(1000)).map((item, i) => {});
[...Array(n)]
[...Array(1000)].map((item, i) => {});
Array(n).fill(null)
Array(1000).fill(null).map((item, i) => {});
Array.from({ length: n })
Array.from({ length: 1000 }).map((item, i) => {});
Array.from({ length:n }, (item, i) => i)
Array.from({ length:1000 }, (item, i) => {});
Array.push
const arr = [] for (let i = 0; i < 1000; ++i) arr.push({})
Array with length + push
const arr = new Array(1000); for (let i = 0; i < 1000; ++i) arr.push({})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Array.apply(null, Array(n))
[...Array(n)]
Array(n).fill(null)
Array.from({ length: n })
Array.from({ length:n }, (item, i) => i)
Array.push
Array with length + push

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36

Browser/OS: Chrome 132 on Mac OS X 10.15.7

View result in a separate tab

Array(n).fill(null)

386K/s

[...Array(n)]

375K/s

Array.push

326K/s

Array with length + push

262K/s

Array.apply(null, Array(n))

246K/s

Array.from({ length: n })

40K/s

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

35K/s

View exact numbers

Test name	Executions per second
✓ Array(n).fill(null)	386,269 Ops/sec
[...Array(n)]	375,067 Ops/sec
Array.push	325,621 Ops/sec
Array with length + push	262,179 Ops/sec
Array.apply(null, Array(n))	245,904 Ops/sec
Array.from({ length: n })	40,169 Ops/sec
Array.from({ length:n }, (item, i) => i)	34,888 Ops/sec