Run results for: test Map vs Object with string which use string as key and value

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser: Chrome 133

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

Map get

532K/s

Obj get

147K/s

Obj set

136K/s

Map set

93K/s

View exact numbers

Test name	Executions per second
✓ Map get	531,689 Ops/sec
Obj get	146,711 Ops/sec
Obj set	135,565 Ops/sec
Map set	92,559 Ops/sec

Script Preparation code:

const map = new Map();
const obj = {};

function generateKeys(startIndex, endIndex) {
  const res = [];
  for (let i = startIndex; i < endIndex; i++) {
    res.push(btoa(i));
  }

  return res;
}

const kvs = generateKeys(0, 1000);
const newKvs = generateKeys(10000, 12000);

kvs.forEach(kv => {
  map.set(kv, kv);
  obj[kv] = kv;
});

Tests:

Map get
kvs.forEach(kv => { map.get(kv); });
Obj get
kvs.forEach(kv => { obj[kv]; });
Map set
kvs.forEach(kv => { map.set(kv, kv); });
Obj set
kvs.forEach(kv => { obj[kv] = kv; });