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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 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36 OPR/109.0.0.0
Opera 109
Windows
Desktop
5 months ago
Test name Executions per second
typeof string is undefined 27985352.0 Ops/sec
typeof undefined is undefined 1840930.5 Ops/sec
string is undefined 1882830.9 Ops/sec
undefined is undefined 992269.0 Ops/sec
Tests:

  • typeof string is undefined

  • typeof undefined is undefined

  • string is undefined

  • undefined is undefined