Run results for: contains misses: Map vs Set vs Array vs Symbol vs UID

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36

Browser: Chrome 95

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
map	3399315.2 Ops/sec
set	3278660.2 Ops/sec
arr	336394.8 Ops/sec
symbol	3618213.5 Ops/sec
uid	3571403.8 Ops/sec
control	5426366.5 Ops/sec

Script Preparation code:

var
map = new Map(),
set = new Set(),
arr = [],
sym = Symbol(),
uid = "some-uid",
item = {};	// not in any

// Create
for (var i = 0; i < 5000; ++i)
{
  var obj = {};
  map.set(obj, true);
  set.add(obj);
  arr.push(obj);
  obj[sym] = true;
  obj[uid] = true;
}

function mapHas(thing)
{
  return map.has(thing);
}

function setHas(thing)
{
  return set.has(thing);
}

function arrHas(thing)
{
  return arr.indexOf(thing) >= 0;
}

function symHas(thing)
{
  return thing[sym];
}

function uidHas(thing)
{
  return thing[uid];
}

function conHas(thing)
{
  return false;
}

Tests:

map
mapHas(item);
set
setHas(item);
arr
arrHas(item);
symbol
symHas(item);
uid
uidHas(item);
control
conHas(item);

Run results for: contains misses: Map vs Set vs Array vs Symbol vs UID

map

set

arr

symbol

uid

control