Run results for: flatten arrays 11241243

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36

Browser: Chrome 79

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Array.flat()	784.2 Ops/sec
Reduce	39239.1 Ops/sec
forEach	17066.3 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));

Run results for: flatten arrays 11241243

Array.flat()

Reduce

forEach