Run results for: `Array.slice(0, N)` vs `Array.length = N`

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0

Browser: Firefox 135

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

`Array.length = N`

62.1M/s

`Array.slice(0, N)`

26.5M/s

`Object.assign([], arr)` with `Array.length = N`

664K/s

View exact numbers

Test name	Executions per second
✓ `Array.length = N`	62,108,124 Ops/sec
`Array.slice(0, N)`	26,477,164 Ops/sec
`Object.assign([], arr)` with `Array.length = N`	664,380 Ops/sec

Script Preparation code:

var arr = Array.from(Array(100).keys());

Tests:

`Array.slice(0, N)`
arr.slice(0, 20);
`Array.length = N`
arr.length = 20;
`Object.assign([], arr)` with `Array.length = N`
var newArr = Object.assign([], arr); newArr.length = 20;