Run results for: Object vs Map - creation with dynamic keys

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:147.0) Gecko/20100101 Firefox/147.0

Browser: Firefox 147

Operating system: Windows

Device Platform: Desktop

Date tested: 7 months ago

Benchmark engine: Benchmark.js

Map constructor - creation

157K/s

Empty Map + loop insert - creation

154K/s

Empty object - creation

149K/s

Object with eval hack - creation

93K/s

Map constructor - lookup

39K/s

Empty Map + loop insert - lookup

39K/s

Empty object - lookup

29K/s

Eval hack - lookup

12K/s

View exact numbers

Test name	Executions per second
✓ Map constructor - creation	157,437 Ops/sec
Empty Map + loop insert - creation	154,122 Ops/sec
Empty object - creation	148,925 Ops/sec
Object with eval hack - creation	93,489 Ops/sec
Map constructor - lookup	38,870 Ops/sec
Empty Map + loop insert - lookup	38,849 Ops/sec
Empty object - lookup	28,887 Ops/sec
Eval hack - lookup	11,986 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

const keys = new Array(100);
for(let i = 0; i < 100; i++) {
  keys[i] = Math.random().toString(36).slice(2); 
}

const lookupKeys = new Array(500);
for(let i = 0; i < 500; i++) {
  lookupKeys[i] = Math.random() < 0.2 ? keys[Math.floor(Math.random() * 100)] : Math.random().toString(36).slice(2);
}

Tests:

Empty Map + loop insert - creation
const map = new Map(); for(let i = 0, keyLen = keys.length; i < keyLen; i++) { map.set(keys[i], true); }
Map constructor - creation
const map = new Map(keys.map((k) => [k, true]));
Object with eval hack - creation
const obj = eval(`({ ${keys.map((k) => `"${k}": true`).join(", ")} })`);
Empty Map + loop insert - lookup
const map = new Map(); for(let i = 0, keyLen = keys.length; i < keyLen; i++) { map.set(keys[i], true); } let hits = 0; for(const k of lookupKeys) { if(map.get(k)) { hits++; } }
Map constructor - lookup
const map = new Map(keys.map((k) => [k, true])); let hits = 0; for(const k of lookupKeys) { if(map.get(k)) { hits++; } }
Eval hack - lookup
const obj = eval(`({ ${keys.map((k) => `"${k}": true`).join(", ")} })`); let hits = 0; for(const k of lookupKeys) { if(obj[k]) { hits++; } }
Empty object - creation
const obj = {}; for(let i = 0, keyLen = keys.length; i < keyLen; i++) { obj[keys[i]] = true; }
Empty object - lookup
const obj = {}; for(let i = 0, keyLen = keys.length; i < keyLen; i++) { obj[keys[i]] = true; } let hits = 0; for(const k of lookupKeys) { if(obj[k]) { hits++; } }