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

Run details:

User agent: Mozilla/5.0 (Linux; Android 9; Mi A2 Lite Build/PKQ1.180917.001) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.71 Mobile Safari/537.36

Browser: Chrome Mobile 63

Operating system: Android

Device Platform: Mobile

Date tested: 4 years ago

Test name	Executions per second
undefined	531531.8 Ops/sec
typeof	1815495.6 Ops/sec
in	1671155.1 Ops/sec
hasOwnProperty	1673920.4 Ops/sec
bool	1806989.5 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