Run results for: Instanceof vs string comparison vs property checking vs constructor comparison

Measure the performance of instanceOf operator vs comparing a basic string type.

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Run details:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36
Chrome 136
Mac OS X 10.15.7
Desktop
one year ago
Test name Executions per second
instanceof Promise (promise) 303837824.0 Ops/sec
instanceof Promise (empty object) 241658960.0 Ops/sec
instanceof Promise (null) 290129280.0 Ops/sec
then check (promise) 298302976.0 Ops/sec
then check (empty object) 254150944.0 Ops/sec
then check (null) 265423008.0 Ops/sec
constructor comparison (promise) 277396320.0 Ops/sec
constructor comparison (empty object) 260667152.0 Ops/sec
constructor comparison (null) 273117664.0 Ops/sec
type obj?.then === function (promise) 269327680.0 Ops/sec
type obj?.then === function (empty object) 257449760.0 Ops/sec
type obj?.then === function (null) 260597456.0 Ops/sec
then in (promise) 277073248.0 Ops/sec
then in (empty object) 262307344.0 Ops/sec
then in (null) 285495616.0 Ops/sec
Script Preparation code:
Tests:

  • instanceof Promise (promise)

  • instanceof Promise (empty object)

  • instanceof Promise (null)

  • then check (promise)

  • then check (empty object)

  • then check (null)

  • constructor comparison (promise)

  • constructor comparison (empty object)

  • constructor comparison (null)

  • type obj?.then === function (promise)

  • type obj?.then === function (empty object)

  • type obj?.then === function (null)

  • then in (promise)

  • then in (empty object)

  • then in (null)

  • instanceof Promise (undefined)

  • then check (undefined)

  • constructor comparison (undefined)

  • type obj?.then === function (undefined)

  • then in (undefined)