Run results for: Undefined testing - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.40 Safari/537.36

Browser: Chrome 67

Operating system: Windows

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
typeof x === "undefined"	11720510.0 Ops/sec
x === undefined	3485459.0 Ops/sec
x == undefined	3405606.0 Ops/sec
x == null	11629260.0 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