Run results for: Methods to remove duplicates object with a key from array

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser: Chrome 122

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Using a Set

801/s

Using reduce

451/s

Using filter and findIndex

429/s

View exact numbers

Test name	Executions per second
✓ Using a Set	801 Ops/sec
Using reduce	451 Ops/sec
Using filter and findIndex	429 Ops/sec

Script Preparation code:

var array = [];
for (let i = 0; i < 100000; i++) {
    array.push({
        id: Math.floor((Math.random() * 10) + 1),
        someOtherKey: "someOtherValue"
    });
}

Tests:

Using a Set
function removeDuplicates(items) { const seenIds = new Set(); const result = []; for (const item of items) { if (!seenIds.has(item.id)) { seenIds.add(item.id); result.push(item); } } return result; } removeDuplicates(array)
Using filter and findIndex
array.filter((item, index, array) => array.findIndex(i => i.id === item.id) === index );
Using reduce
array.reduce((acc, currentItem) => { const isDuplicate = acc.some(item => item.id === currentItem.id); if (!isDuplicate) { acc.push(currentItem); } return acc; }, []);