MeasureThat.net

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

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

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Run details:
Mozilla/5.0 (X11; Linux x86_64; rv:92.0) Gecko/20100101 Firefox/92.0
Firefox 92
Linux
Desktop
3 years ago
Test name Executions per second
typeof string is undefined 1863279616.0 Ops/sec
typeof undefined is undefined 1846715776.0 Ops/sec
string is undefined 1846625152.0 Ops/sec
undefined is undefined 1857575680.0 Ops/sec
Tests:

  • typeof string is undefined

    AخA
     
    typeof "not undefined" === "undefined"

  • typeof undefined is undefined

     
    typeof undefined === "undefined"

  • string is undefined

     
    "not undefined" === undefined

  • undefined is undefined

     
    undefined === undefined