Run results for: array filtering v3

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_1_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.192 Safari/537.36

Browser: Chrome 88

Operating system: Mac OS X 11.1.0

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Boolean	77058.9 Ops/sec
x => !!x	179355.5 Ops/sec
x => x	299982.2 Ops/sec
delete + .flat	4750.3 Ops/sec

Script Preparation code:

var arr = new Array(1000).fill(undefined)
const falsy = [false, "", 0, null, undefined]
const truthy = [true, "string", 10, {}, []]

for (let i = arr.length; i--;) {
	const useFalsy = Math.random() < 0.5
	const source = useFalsy ? falsy : truthy
	const index = Math.floor(Math.random() * source.length)
	arr[i] = source[index]
}

Tests:

Boolean
arr.filter(Boolean)
x => !!x
arr.filter(x => !!x)
x => x
arr.filter(x => x)
delete + .flat
for (let i = arr.length; i--;) if (!arr[i]) delete arr[i] arr.flat()
own - preserve length
const {length} = arr , filtered = new Array(length) let count = 0 for (let i = 0; i < length; i++) { const val = arr[i] if (val) filtered[count++] = val } filtered.length = count
own
const {length} = arr , filtered = [] let count = 0 for (let i = 0; i < length; i++) { const val = arr[i] if (val) filtered[count++] = val }

Run results for: array filtering v3

Compare array filtering: - Boolean - x => !!x - x => x - delete + .flat - own preserve length - own

Boolean

x => !!x

x => x

delete + .flat

own - preserve length

own