Run results for: Dedup Array of Objects (4 strats)

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/132.0.0.0 Safari/537.36

Browser: Chrome 132

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Object lookup

16K/s

Filter + Set

16K/s

Array from Map

12K/s

Naive Filter

27/s

View exact numbers

Test name	Executions per second
✓ Object lookup	16,008 Ops/sec
Filter + Set	15,588 Ops/sec
Array from Map	11,636 Ops/sec
Naive Filter	27 Ops/sec

Script Preparation code:

const ids = Array.from({
    length: 1000
}, () => Math.random().toString(16).slice(2));
const array = [...ids.map((id) => ([{
                id: id,
                content: "foo"
            }, {
                id: id,
                content: "bar"
            }, {
                id: id,
                content: "baz"
            }]))].flat();

Tests:

Filter + Set
const seen = new Set(); const deduplicatedArray1 = array.filter(item => { if (seen.has(item.id)) { return false; } seen.add(item.id); return true; });
Array from Map
const deduplicatedArray2 = [ ...new Map(array.map(item => [item.id, item])).values() ];
Naive Filter
const deduplicatedArray3 = array.filter((item, index, self) => index === self.findIndex(obj => obj.id === item.id) );
Object lookup
const deduplicatedArray4 = []; const seen = {}; for (const item of array) { if (!seen[item.id]) { deduplicatedArray4.push(item); seen[item.id] = true; } }