Run results for: Symbol vs Object identity access speed

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:123.0) Gecko/20100101 Firefox/123.0

Browser: Firefox 123

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Symbol read: Set

143K/s

Symbol read: Map

134K/s

Object read: Set

97K/s

Object read: Map

96K/s

Symbol read: Object

74K/s

Symbol write: Object

69K/s

Symbol insert: Set

65K/s

Symbol write: Set

65K/s

Symbol insert: Map

56K/s

Symbol insert: Object

55K/s

Symbol write: Map

53K/s

Object insert: Set

53K/s

Object write: Set

49K/s

Object insert: Map

45K/s

Object write: Map

43K/s

View exact numbers

Test name	Executions per second
✓ Symbol read: Set	142,847 Ops/sec
Symbol read: Map	134,411 Ops/sec
Object read: Set	96,864 Ops/sec
Object read: Map	95,626 Ops/sec
Symbol read: Object	74,141 Ops/sec
Symbol write: Object	68,587 Ops/sec
Symbol insert: Set	64,929 Ops/sec
Symbol write: Set	64,845 Ops/sec
Symbol insert: Map	55,977 Ops/sec
Symbol insert: Object	54,931 Ops/sec
Symbol write: Map	52,931 Ops/sec
Object insert: Set	52,553 Ops/sec
Object write: Set	49,481 Ops/sec
Object insert: Map	44,809 Ops/sec
Object write: Map	43,045 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);