Run results for: Array concat vs spread vs push spread, loop, apply

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 15_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/98.0.4758.85 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 98

Operating system: iOS 15.2

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
Array.prototype.concat	2897952.0 Ops/sec
spread operator	2836714.0 Ops/sec
Push Spread	1867616.0 Ops/sec
Push Apply	2166199.0 Ops/sec
Push Loop	3005780.0 Ops/sec

Script Preparation code:

var subarrs = [
 [ "hello", true, 7 ],
 [ "yes", "no", "maybe", false, 27 ],
 [ 16, "I", "wonder", "what", "will", "be", "fastest"]
];

Tests:

Array.prototype.concat
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other = other.concat(subarrs[i]); } return other;
spread operator
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other = [ ...other, ...subarrs[i] ] } return other;
Push Spread
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other.push(...subarrs[i]); } return other;
Push Apply
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ other.push.apply(other, subarrs[i]); } return other;
Push Loop
var other = [ 1, 2, 3 ] for (var len = subarrs.length, i = 0; i < len; i++){ for (var jarr = subarrs[i], jen = jarr.length, j = 0; j < jen; j++){ other.push(jarr[j]); } } return other;

Run results for: Array concat vs spread vs push spread, loop, apply

Compare the new ES6 spread operator with the traditional concat() method and push

Array.prototype.concat

spread operator

Push Spread

Push Apply

Push Loop