Run results for: map vs. for vs. for in vs. forEach - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0

Browser: Firefox 47

Operating system: Windows

Device Platform: Other

Date tested: 7 years ago

Test name	Executions per second
map	31539770.0 Ops/sec
for in	415922.9 Ops/sec
for	25056260.0 Ops/sec
forEach	23398150.0 Ops/sec

Website performance monitoring

Script Preparation code:

var a = ["foo", "bar", "baz", "boom"]

Tests:

map
var b = a.map(function(c) { return c; });
for in
var b = []; for (var i in a) { b.push(a[i]); }
for
var b = []; for (var i = 0; i < a.length; i++) { b.push(a[i]); }
forEach
var b = []; a.forEach(function(c) { b.push(c); });