Run results for: Map vs Object with random keys

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36

Browser: Chrome 101

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Map insert	1169.1 Ops/sec
Obj insert	1110.8 Ops/sec
Map delete	23926.9 Ops/sec
Obj delete using delete	17133.8 Ops/sec
Extra: Object delete assimiling undefined	5448.7 Ops/sec
Map lookup	26764.9 Ops/sec
Object lookup	20476.3 Ops/sec
Map check	26678.5 Ops/sec
Object check(key in) non-secure	20513.0 Ops/sec
Object check using hasOwnProperty	18333.2 Ops/sec
Object check using hasOwnProperty secure implementation	8257.8 Ops/sec

Script Preparation code:

var insertMap = new Map();
var insertObj = {};

var ID = function () {
  return '_' + Math.random().toString(36).substr(2, 9);
};

var toLookupMap = new Map();
var toLookupObj = {};
var toLookupKeys = [];
var toDeleteMap = new Map();
var toDeleteObj = {};
var toDeleteKeys = [];

var i = 0, count = 1000;

for (i = 0; i < count; i++) {
  var key = ID();
  toDeleteMap.set(key, 0);
  toDeleteObj[key] = 0;
  toDeleteKeys.push(key);

  var key2 = ID();
  toLookupMap.set(key2, 0);
  toLookupObj[key2] = 0;
  toLookupKeys.push(key2);
}

Tests:

Map insert
for (i = 0; i < count; i++) { insertMap.set(ID(), 0); }
Obj insert
for (i = 0; i < count; i++) { insertObj[ID()] = 0; }
Map delete
toDeleteKeys.forEach(function (key) { toDeleteMap.delete(key); });
Obj delete using delete
toDeleteKeys.forEach(function (key) { delete toDeleteObj[key]; });
Extra: Object delete assimiling undefined
toDeleteKeys.forEach(function (key) { toDeleteObj[key] = undefined; });
Map lookup
toLookupKeys.forEach(function (key) { toLookupMap.get(key); });
Object lookup
toLookupKeys.forEach(function (key) { toLookupObj[key]; });
Map check
toLookupKeys.forEach(function (key) { toLookupMap.has(key); });
Object check(key in) non-secure
toLookupKeys.forEach(function (key) { key in toLookupObj; });
Object check using hasOwnProperty
toLookupKeys.forEach(function (key) { toLookupObj.hasOwnProperty(key); });
Object check using hasOwnProperty secure implementation
toLookupKeys.forEach(function (key) { Object.prototype.hasOwnProperty.call(toLookupObj, key); });

Run results for: Map vs Object with random keys

Insert/delete of map vs object

Map insert

Obj insert

Map delete

Obj delete using delete

Extra: Object delete assimiling undefined

Map lookup

Object lookup

Map check

Object check(key in) non-secure

Object check using hasOwnProperty

Object check using hasOwnProperty secure implementation