Run results for: Array concat vs spread operator vs push - with large arrays5

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/88.0.4324.150 Safari/537.36

Browser: Chrome 88

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
Array.prototype.concat	21627.0 Ops/sec
spread operator	11372.1 Ops/sec
Push	13855.3 Ops/sec
spread operator without push setup	16692.9 Ops/sec

Script Preparation code:

var array1 = [0,1,2,3,4,5,6,7,8,9]; 
for (var i=0;i<10;i++) array1.push(...array1);
var array2 = [...array1];
console.log('array1.length = ' + array1.length)

Tests:

Array.prototype.concat
var result = array1.concat(array2); // the 'push' test needs to do more setup. Repeat it here so it's not unfairly hindered. var pushResult = []; pushResult.push(...array1);
spread operator
var result = [...array1, ...array2]; // the 'push' test needs to do more setup. Repeat it here so it's not unfairly hindered. var pushResult = []; pushResult.push(...array1);
Push
// setup for push var pushResult = []; pushResult.push(...array1); // push test: pushResult.push(...array2);
spread operator without push setup
var result = [...array1, ...array2];
push without setup
var result = array1.push(...array2);

Run results for: Array concat vs spread operator vs push - with large arrays5

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

Array.prototype.concat

spread operator

Push

spread operator without push setup

push without setup