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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 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.6 Safari/605.1.15
Safari 17
Mac OS X 10.15.7
Desktop
3 months ago
Test name Executions per second
typeof string is undefined 509141920.0 Ops/sec
typeof undefined is undefined 7954933.0 Ops/sec
string is undefined 7806346.5 Ops/sec
undefined is undefined 3981926.2 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