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

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.0.0; SAMSUNG SM-G935F) AppleWebKit/537.36 (KHTML, like Gecko) SamsungBrowser/11.2 Chrome/75.0.3770.143 Mobile Safari/537.36

Browser: Chrome Mobile 75

Operating system: Android 8.0.0

Device Platform: Mobile

Date tested: 3 years ago

Test name	Executions per second
undefined	1623491.0 Ops/sec
typeof	4303760.0 Ops/sec
in	4516981.0 Ops/sec
hasOwnProperty	4147769.0 Ops/sec
bool	4499844.0 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