Run results for: undefined vs. typeof vs. in vs. hasOwnProperty - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0

Browser: Firefox 67

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
undefined	145463000.0 Ops/sec
typeof	276247700.0 Ops/sec
in	206361400.0 Ops/sec
hasOwnProperty	199532700.0 Ops/sec
bool	279488000.0 Ops/sec

Website performance monitoring

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;