Run results for: Undefined testing - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36

Browser: Chrome 74

Operating system: Windows 7

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
typeof x === "undefined"	8563068.0 Ops/sec
x === undefined	3240892.0 Ops/sec
x == undefined	3270093.0 Ops/sec
x == null	8883155.0 Ops/sec

Website performance monitoring

Script Preparation code:

var x;
var y = {};

Tests:

typeof x === "undefined"
typeof x === "undefined"
x === undefined
x === undefined
x == undefined
x == undefined
x == null
x == null