Run results for: undefined vs. typeof vs. in vs. hasOwnProperty vs Object.prototype.hasOwnProperty

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser: Chrome 103

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
undefined	3888632.0 Ops/sec
typeof	11176710.0 Ops/sec
in	11368960.0 Ops/sec
hasOwnProperty	10155210.0 Ops/sec
bool	11388570.0 Ops/sec
Object.prototype.hasOwnProperty	2186509.0 Ops/sec

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };
function hasOwn (obj, key) {
  return hasOwnProperty.call(obj, key)
}

Tests: