Run results for: Filter array using includes vs object lookup

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser: Chrome 125

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 6 months ago

Test name	Executions per second
Filter using array includes	2248749.5 Ops/sec
Filter using object lookup	4946202.5 Ops/sec

Script Preparation code:

var a = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']
var b = ['h', 'i', 'j']

Tests:

Filter using array includes
a.filter((item) => !b.includes(item))
Filter using object lookup
const obj_b = b.reduce((acc, item) => { acc[item] = true return acc }, {}) a.filter((item) => !obj_b[item])