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 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36
Chrome 97
Mac OS X 10.15.7
Desktop
2 years ago
Test name Executions per second
typeof string is undefined 1395695744.0 Ops/sec
typeof undefined is undefined 5766779.0 Ops/sec
string is undefined 6215946.0 Ops/sec
undefined is undefined 3080357.0 Ops/sec
Tests:

  • typeof string is undefined

  • typeof undefined is undefined

  • string is undefined

  • undefined is undefined

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