Run results for: Filter Boolean vs. Custom Function

Run details:

User agent: Mozilla/5.0 (Android 14; Mobile; rv:129.0) Gecko/129.0 Firefox/129.0

Browser: Firefox Mobile 129

Operating system: Android

Device Platform: Mobile

Date tested: 2 months ago

Test name	Executions per second
filter(Boolean)	3823.7 Ops/sec
filter function	4234.8 Ops/sec

Script Preparation code:

var arr = Array.from({length: 10000}, () => Math.random() > 0.5 ? null : "foo");

Tests:

filter(Boolean)
const numTruthy = arr.filter(Boolean).length; console.log(numTruthy);
filter function
const numTruthy = arr.filter(x => !!x).length; console.log(numTruthy);