Benchmark str concatenation

bench.js

var Benchmark = require('benchmark');

var suite = new Benchmark.Suite,
    a, b;

suite
.add('push', function () {
  a = [];
  for (var i = 0; i < 100; i++)
    a.push('Text\n');
  b = a.join();
})
.add('add', function () {
  b = '';
  for (var i = 0; i < 100; i++)
    b += 'Text\n';
})
.on('cycle', function (event, bench) {
  console.log(bench.toString());
})
.on('complete', function () {
  console.log('Fastest is ' + this.filter('fastest').pluck('name'));
})
.run();

Results:

>node bench
push x 638,572 ops/sec ±1.24% (55 runs sampled)
add x 842,122 ops/sec ±3.33% (48 runs sampled)
Fastest is add

Adding is faster by about 30% for this use case (equivalent to concatenating 100 lines of something).

Speed improvement is better when concatenating longer strings:

str = 'TextTextTextTextTextTextTextTextTextTextTextTextTextTextText\n';

gives

>node bench
push x 405,356 ops/sec ±0.95% (55 runs sampled)
add x 885,074 ops/sec ±0.84% (61 runs sampled)
Fastest is add

which is now better than 2x faster.