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

Run details:

User agent: Mozilla/5.0 (Linux; Android 5.1.1; SM-J320G Build/LMY47V) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.132 Mobile Safari/537.36

Browser: Chrome Mobile 57

Operating system: Android 5.1.1

Device Platform: Samsung SM-J320G

Date tested: 7 years ago

Test name	Executions per second
undefined	290283.5 Ops/sec
typeof	762321.6 Ops/sec
in	687515.3 Ops/sec
hasOwnProperty	685376.8 Ops/sec
bool	764557.4 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