Run results for: Better set.has vs array.includes

It often does not make sense to just compare only includes vs has. If we can not create the Set beforehand to be reused, and we need to initialize it every time, it will probably deteriorate the performance and we are better off using just simple include most of the times.

Go to the benchmark

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; rv:124.0) Gecko/20100101 Firefox/124.0

Browser: Firefox 124

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

includes

7.8M/s

lookup

453K/s

View exact numbers

Test name	Executions per second
✓ includes	7,781,298 Ops/sec
lookup	453,092 Ops/sec

Script Preparation code:

function generateRandomData(length) {
    const data = [];
    const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';

    for (let i = 0; i < length; i++) {
        let randomString = '';
        for (let j = 0; j < 20; j++) {
            randomString += characters.charAt(Math.floor(Math.random() * characters.length));
        }
        data.push({ value: randomString });
    }

    return data;
}

var data = generateRandomData(20);
var stringToBeChecked = data[15];

Tests:

includes
const a = data.map(x => x.value); return a.includes(stringToBeChecked);
lookup
const b = new Set(data.map(x => x.value)); return b.has(stringToBeChecked);