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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36

Browser: Chrome 70

Operating system: Mac OS X 10.13.6

Device Platform: Desktop

Date tested: 6 years ago

Test name	Executions per second
undefined	5526792.0 Ops/sec
typeof	18511898.0 Ops/sec
in	16977974.0 Ops/sec
hasOwnProperty	16487414.0 Ops/sec
bool	17790634.0 Ops/sec
Object.prototype.hasOwnProperty	3047475.8 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: