MeasureThat.net

Run results for: is variable undefined? typeof variable === "undefined" vs variable === undefined. WIth variable

Comparing whether checking is (typeof variable === "undefined") is faster than (variable === undefined)

Go to the benchmark
Run details:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36
Chrome 114
Mac OS X 10.15.7
Desktop
one year ago
Test name Executions per second
typeof string is undefined 1035502784.0 Ops/sec
typeof undefined is undefined 1029543552.0 Ops/sec
string is undefined 18126920.0 Ops/sec
undefined is undefined 18099982.0 Ops/sec
Tests:

  • typeof string is undefined

    AخA
     
    let x = "not undefined";
    typeof x === "undefined"

  • typeof undefined is undefined

     
    let x;
    typeof x === "undefined"

  • string is undefined

     
    let x = "not undefined";
    x === undefined

  • undefined is undefined

     
    let x;
    x === undefined