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

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.0.0; F5121 Build/34.4.A.2.118) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.5735.196 Mobile Safari/537.36 OPX/2.0

Browser: Chrome Mobile 114

Operating system: Android 8.0.0

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
undefined	1211188.4 Ops/sec
typeof	3981433.8 Ops/sec
in	3961810.8 Ops/sec
hasOwnProperty	2568944.0 Ops/sec
bool	2718611.2 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