Run results for: flatten arrays 112412432

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36

Browser: Chrome 74

Operating system: Mac OS X 10.14.5

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Array.flat()	993.8 Ops/sec
Reduce	47679.8 Ops/sec
forEach	21102.5 Ops/sec
for	20595.5 Ops/sec
Nested for	990.0 Ops/sec

Script Preparation code:

var entries = 1000;
var a = [];
var b = [];
var c = [];
var d = [];
var e = [];
var f = [];
for (var i = 0; i < entries; i++) {
  a[i] = Math.random();
  b[i] = Math.random();
  c[i] = Math.random();
  d[i] = Math.random();
  e[i] = Math.random();
  f[i] = Math.random();
}
 var arrayOfArrays = [a, b, c, d, e, f];

Tests:

Array.flat()
var result1 = arrayOfArrays.flat();
Reduce
var result2 = arrayOfArrays.reduce((a, subArray) => a.concat(subArray), []);
forEach
var result3 = []; arrayOfArrays.forEach((subArray) => Array.prototype.push.apply(result3, subArray));
for
var result4 = []; for (var i = 0; i < arrayOfArrays.length; i++) { Array.prototype.push.apply(result4, arrayOfArrays[i]); }
Nested for
var result5 = []; for (var i = 0; i < arrayOfArrays.length; i++) { for (var j = 0; j < arrayOfArrays[i].length; j++) { result5.push(arrayOfArrays[i][j]); } }

Run results for: flatten arrays 112412432

Array.flat()

Reduce

forEach

for

Nested for