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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/15.1 Safari/605.1.15
Safari 15
Mac OS X 10.15.7
Desktop
3 years ago
Test name Executions per second
typeof string is undefined 422025760.0 Ops/sec
typeof undefined is undefined 13664021.0 Ops/sec
string is undefined 13667171.0 Ops/sec
undefined is undefined 7144645.0 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