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

Run details:

User agent: Mozilla/5.0 (Linux; Android 12; M2103K19PG Build/SP1A.210812.016) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.88 Mobile Safari/537.36

Browser: Chrome Mobile 99

Operating system: Android

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
undefined	1721465.0 Ops/sec
typeof	5656600.0 Ops/sec
in	5609665.0 Ops/sec
hasOwnProperty	4579145.0 Ops/sec
bool	5525434.0 Ops/sec

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };

Tests:

undefined
undefined !== obj.d;
typeof
'undefined' !== typeof obj.d;
in
'd' in obj;
hasOwnProperty
obj.hasOwnProperty( 'd' );
bool
!! obj.d;

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

Object lookup performance

undefined

typeof

in

hasOwnProperty

bool