Run results for: Symbol vs Object identity access speed

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

Object read: Set

294K/s

Object insert: Set

222K/s

Object write: Set

214K/s

Symbol read: Object

212K/s

Object read: Map

209K/s

Symbol write: Object

198K/s

Symbol insert: Object

197K/s

Object insert: Map

168K/s

Object write: Map

160K/s

Symbol read: Set

129K/s

Symbol read: Map

126K/s

Symbol write: Set

122K/s

Symbol insert: Set

120K/s

Symbol insert: Map

88K/s

Symbol write: Map

87K/s

View exact numbers

Test name	Executions per second
✓ Object read: Set	293,976 Ops/sec
Object insert: Set	222,465 Ops/sec
Object write: Set	213,914 Ops/sec
Symbol read: Object	211,578 Ops/sec
Object read: Map	208,615 Ops/sec
Symbol write: Object	198,248 Ops/sec
Symbol insert: Object	197,098 Ops/sec
Object insert: Map	168,228 Ops/sec
Object write: Map	159,649 Ops/sec
Symbol read: Set	128,680 Ops/sec
Symbol read: Map	126,022 Ops/sec
Symbol write: Set	121,811 Ops/sec
Symbol insert: Set	119,531 Ops/sec
Symbol insert: Map	88,007 Ops/sec
Symbol write: Map	87,429 Ops/sec

Script Preparation code:

var objects = [];
var symbols = [];
var symbolObj = {__proto__: null};
var symbolMap = new Map();
var symbolSet = new Set();
var objectMap = new Map();
var objectSet = new Set();
var emptyObj = {__proto__: null};
var emptyMap = new Map();
var emptySet = new Set();

for (let i = 0; i < 1000; i++) {
  objects[i] = {i, sym: Symbol(i)};
  symbols[i] = objects[i].sym;
  symbolObj[symbols[i]] = i;
  symbolSet.add(symbols[i]);
  symbolMap.set(symbols[i], i);
  objectSet.add(objects[i]);
  objectMap.set(objects[i], i);
}

function objRead(obj, keys) {
  let total = 0;
  for (const key of keys) {
    total += obj[key];
  }
  return total;
}
function objWrite(obj, keys) {
  for (const key of keys) {
    obj[key] = true;
  }
}
function mapRead(map, keys) {
  let total = 0;
  for (const key of keys) {
    total += map.get(key);
  }
  return total;
}
function mapWrite(map, keys) {
  for (const key of keys) {
    map.set(key, true);
  }
}
function setRead(set, keys) {
  let total = 0;
  for (const key of keys) {
    total += set.has(key) ? 1 : 0;
  }
  return total;
}
function setWrite(set, keys) {
  for (const key of keys) {
    set.add(key);
  }
}

Tests:

Symbol read: Object
objRead(symbolObj, symbols)
Symbol read: Set
setRead(symbolSet, symbols)
Symbol read: Map
mapRead(symbolMap, symbols)
Object read: Set
setRead(objectSet, objects)
Object read: Map
mapRead(objectMap, objects)
Symbol write: Object
objWrite(symbolObj, symbols)
Symbol write: Set
setWrite(symbolSet, symbols)
Symbol write: Map
mapWrite(symbolMap, symbols);
Object write: Set
setWrite(objectSet, objects);
Object write: Map
mapWrite(objectMap, objects);
Symbol insert: Object
objWrite(emptyObj, symbols);
Symbol insert: Set
setWrite(emptySet, symbols);
Symbol insert: Map
mapWrite(emptyMap, symbols);
Object insert: Set
setWrite(emptySet, objects);
Object insert: Map
mapWrite(emptyMap, objects);