Run results for: Array merge -> Concat | Push spread | Concat Apply | Push Apply | Spread

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Firefox/78.0

Browser: Firefox 78

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Array.prototype.concat	14578525.0 Ops/sec
Array.prototype.push spread	5248007.5 Ops/sec
Array.prototype.concat.apply	8283555.5 Ops/sec
Array.prototype.push.apply	6813417.5 Ops/sec
Spread	19529704.0 Ops/sec
Loop Push	19039560.0 Ops/sec

Script Preparation code:

var params = [ "hello", true, 1, { foo: 'bar' } ];

var concat = (input) => [].concat(params);
var push = (input) => [].push(...input);
var concatApply = (input) => Array.prototype.concat.apply([], input);
var pushApply = (input) => Array.prototype.push.apply([], input);
var spread = (input) => [...input];
var loop = (input) => {
  var acc = [];
  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

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