V8 Optimization Killers

Re:V8 Optimization Killers by kipple on Wednesday June 25, 2014 @12:26PM (#7944969)

Is a plain for loop with a counter significantly faster than a forEach? With Object.keys I've been enjoying the simplicity of statements like

  Object.keys(obj).forEach(function (key) {
    console.log(obj[key]);
  });

but does that hamstring my performance?

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Re:V8 Optimization Killers by bzbarsky on Wednesday June 25, 2014 @01:08PM (#7945291)

Your mileage will vary depending on the browser. If you really care (as in profiling identified this as a hotspot) you should measure the alternatives you're considering.

But note that in your specific case chances are the cost of a bunch of console.log() calls completely swamps the cost of either a for loop or a forEach call. console.log() has _incredibly_ complicated behavior.

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Re:V8 Optimization Killers by ekmartin on Thursday June 26, 2014 @02:27AM (#7948367)

A native counter for-loop will always be faster: http://jsperf.com/angular-foreach-vs-native-for-loop/13

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