string startsWith() benchmark

bench.js

var Suite = require('benchmark').Suite

function startsWith(prefix, str) {
  for (var i = 0; i < prefix.length; i++) {
    if (prefix[i] != str[i]) return false
  }
  return true
}

var suite = new Suite

suite.add('startsWith()', function() {
  startsWith('hello', 'hello world')
})


suite.add('indexOf() == 0', function(deferred) {
  'hello world'.indexOf('hello') == 0
})

suite.add('regex', function(deferred) {
  /^hello/.test('hello world')
})

suite
.on('cycle', function(event) {
  console.log(String(event.target));
})
.on('complete', function() {
  console.log('Fastest is ' + this.filter('fastest').pluck('name'));
})
.run({async: true})

results

startsWith() x 22,076,291 ops/sec ±0.45% (94 runs sampled)
indexOf() == 0 x 18,575,700 ops/sec ±1.57% (89 runs sampled)
regex x 21,090,471 ops/sec ±0.63% (93 runs sampled)