Run results for: undefined vs typeof vs in vs hasOwnProperty / ver. 2

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser: Chrome 138

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 19 days ago

Test name	Executions per second
undefined	9719.7 Ops/sec
typeof	9126.6 Ops/sec
in	9174.7 Ops/sec
hasOwnProperty	5790.0 Ops/sec
bool	4739.6 Ops/sec

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };
var keys = new Array(4096 * 5);
for (let i = 0; i < keys.length; i += 1)
  keys[i] = Math.random().toString();
for (let i = 0; i < keys.length; i += 2)
  obj[keys[i]] = i;

Tests:

undefined
for (let i = 0; i < 4096; i += 1) obj[keys[4096 * 0 + i]] === undefined;
typeof
for (let i = 0; i < 4096; i += 1) typeof obj[keys[4096 * 1 + i]] === "undefined";
in
for (let i = 0; i < 4096; i += 1) keys[4096 * 2 + i] in obj;
hasOwnProperty
for (let i = 0; i < 4096; i += 1) obj.hasOwnProperty(keys[4096 * 3 + i]);
bool
for (let i = 0; i < 4096; i += 1) !obj[keys[4096 * 4 + i]];

Run results for: undefined vs typeof vs in vs hasOwnProperty / ver. 2

Object lookup performance

undefined

typeof

in

hasOwnProperty

bool