Run results for: Array merge -> Concat | Push spread | Concat Apply | Push Apply | Spread | Loop Push (large array)

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser: Chrome 85

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Array.prototype.concat	2245.9 Ops/sec
Array.prototype.push spread	238.0 Ops/sec
Array.prototype.concat.apply	360.4 Ops/sec
Array.prototype.push.apply	242.2 Ops/sec
Spread	497.5 Ops/sec
Loop Push	493.6 Ops/sec

Script Preparation code:

var params = [];
for ( i = 0; i < 100000; i++ ) {
  params.push(Math.random());
}

var concat = (input) => [1,2,3].concat(params);
var push = (input) => [1,2,3].push(...input);
var concatApply = (input) => Array.prototype.concat.apply([1,2,3], input);
var pushApply = (input) => Array.prototype.push.apply([1,2,3], input);
var spread = (input) => [1,2,3,...input];
var loop = (input) => {
  var acc = [1,2,3];
  for(var i = 0, l = input.length; i < l; i++) {
    acc.push(input[i]);
  }
  return acc;
}

Tests:

Array.prototype.concat
const result = concat(params);
Array.prototype.push spread
const result = push(params);
Array.prototype.concat.apply
const result = concatApply(params);
Array.prototype.push.apply
const result = pushApply(params);
Spread
const result = spread(params);
Loop Push
const result = spread(params);

Run results for: Array merge -> Concat | Push spread | Concat Apply | Push Apply | Spread | Loop Push (large array)

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

Array.prototype.concat

Array.prototype.push spread

Array.prototype.concat.apply

Array.prototype.push.apply

Spread

Loop Push