push.apply

benchmark.js

var Benchmark = require('benchmark');

var suite = new Benchmark.Suite();
var headers0 = [];
var headers1 = ['k1', 'v1'];
var headers = ['k1', 'v1', 'k1', 'v1', 'k1', 'v1', 'k1', 'v1', 'k1', 'v1', 'k1', 'v1'];

// add tests
suite.add('apply 0', function () {
  var raw = [];
  raw.push.apply(raw, headers0);
})
.add('push 0', function () {
  var raw = [];
  for (var i = 0; i < headers0.length; i = i+2) {
    raw.push(headers0[i]);
    raw.push(headers0[i + 1]);
  }
})
.add('apply 1', function () {
  var raw = [];
  raw.push.apply(raw, headers1);
})
.add('push 1', function () {
  var raw = [];
  for (var i = 0; i < headers1.length; i = i+2) {
    raw.push(headers1[i]);
    raw.push(headers1[i + 1]);
  }
})
.add('apply n', function () {
  var raw = [];
  raw.push.apply(raw, headers);
})
.add('push n', function () {
  var raw = [];
  for (var i = 0; i < headers.length; i = i+2) {
    raw.push(headers[i]);
    raw.push(headers[i + 1]);
  }
})
.add('push nn', function () {
  var raw = [];
  for (var i = 0; i < headers.length; i = i+2) {
    raw.push(headers[i], headers[i + 1]);
  }
})
// add listeners
.on('cycle', function(event) {
  console.log(String(event.target));
})
.on('complete', function() {
  console.log('Fastest is ' + this.filter('fastest').pluck('name'));
})
// run async
.run({ 'async': true });
// jacksontian node_research $ node push.js 
// apply 0 x 9,237,973 ops/sec ±1.80% (90 runs sampled)
// push 0 x 45,320,843 ops/sec ±1.95% (83 runs sampled)
// apply 1 x 4,803,977 ops/sec ±2.43% (82 runs sampled)
// push 1 x 18,637,590 ops/sec ±2.41% (76 runs sampled)
// apply n x 3,523,985 ops/sec ±1.93% (85 runs sampled)
// push n x 10,443,368 ops/sec ±1.88% (90 runs sampled)
// push nn x 2,122,618 ops/sec ±1.59% (86 runs sampled)
// Fastest is push 0