Run results for: filter vs reduce vs slice-splice

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.5060.53 Safari/537.36

Browser: Chrome 103

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
filter	158.2 Ops/sec
reduce	157.1 Ops/sec
slice-splice	7.7 Ops/sec

Script Preparation code:

var a = [];
var b = [];

for (var i = 0; i < 1000; i++) {
    var val1 = Math.random().toString(36).slice(2);
    var val2 = Math.random().toString(33).slice(2);
    b.push(val1);
    if (Math.random() > 0.1) {
        b.push(val2);
        a.push(val1);
    } else {
        a.push(val2);
    }
}

Tests:

filter
window.ret = a.filter(val => b.indexOf(val) === -1);
reduce
window.ret = a.reduce((result, item) => { if (b.indexOf(item) === -1) { result.push(item); } return result; }, []);
slice-splice
const result = window.ret = a.slice(); for (let i = 0; i < result.length; i++) { for (let j = 0; j < b.length; j++) { if (result[i] === b[j]) { result.splice(i, 1); i--; break; } } }