Benchmark: for, for of, forEach, and reduce. Each with and without reduced variable re-declarations.

Script Preparation code:

var array = [];
(function(theArray) {
  for (var i = 0, L = 10000; i < L; i += 1) {
    array.push({
      creationIndex: i,
      someStringifiedNumber: (Date.now() + '|' + Math.random())
    });
  }
})(array);
var result;

Tests:

for
var someValuesArray = []; for (var i = 0, L = array.length; i < L; i++) { var someVar = array[i]; var someValue = someVar.creationIndex + someVar.someStringifiedNumber; someValuesArray.push(someValue); } result = someValuesArray;
for (less closure)
var someValuesArray = []; var someVar; var someValue; for (var i = 0, L = array.length; i < L; i++) { someVar = array[i]; someValue = someVar.creationIndex + someVar.someStringifiedNumber; someValuesArray.push(someValue); } result = someValuesArray;
for of
var someValuesArray = []; for (var someVar of array) { var someValue = someVar.creationIndex + someVar.someStringifiedNumber; someValuesArray.push(someValue); } result = someValuesArray;
for of (less closure)
var someValuesArray = []; var someValue for (var someVar of array) { someValue = someVar.creationIndex + someVar.someStringifiedNumber; someValuesArray.push(someValue); } result = someValuesArray;
forEach
var someValuesArray = []; array.forEach(function(someVar) { var someValue = someVar.creationIndex + someVar.someStringifiedNumber; someValuesArray.push(someValue); }); result = someValuesArray;
forEach (less closure)
var someValuesArray = []; var someValue; array.forEach(function(someVar) { someValue = someVar.creationIndex + someVar.someStringifiedNumber; someValuesArray.push(someValue); }); result = someValuesArray;
reduce
var someValuesArray = array.reduce(function(valuesArray, someVar) { var someValue = someVar.creationIndex + someVar.someStringifiedNumber; valuesArray.push(someValue); return valuesArray; }, []); result = someValuesArray;
reduce (less closure)
var someValuesArray = []; var someValue; array.reduce(function(valuesArray, someVar) { someValue = someVar.creationIndex + someVar.someStringifiedNumber; valuesArray.push(someValue); return valuesArray; }, someValuesArray); result = someValuesArray;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
for (less closure)
for of
for of (less closure)
forEach
forEach (less closure)
reduce
reduce (less closure)

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 13_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 13 on iOS 13.7

View result in a separate tab

Test name	Executions per second
for	407.1 Ops/sec
for (less closure)	346.4 Ops/sec
for of	783.1 Ops/sec
for of (less closure)	862.3 Ops/sec
forEach	896.7 Ops/sec
forEach (less closure)	912.0 Ops/sec
reduce	976.7 Ops/sec
reduce (less closure)	914.7 Ops/sec

for, for of, forEach, and reduce. Each with and without reduced variable re-declarations. (version: 1)

Compare loop performance

Comparing performance of: for vs for (less closure) vs for of vs for of (less closure) vs forEach vs forEach (less closure) vs reduce vs reduce (less closure)

Created: 3 years ago by: Registered User

Jump to the latest result

for

for (less closure)

for of

for of (less closure)

forEach

forEach (less closure)

reduce

reduce (less closure)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A