benchmark various regexp syntax.

benchmark-regex-compile.js

var Benchmark = require('benchmark');
Benchmark.prototype.setup = function() {
  l = 100000;
  s = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxtestyyyyyyyyyyyyyyyyyyyyy';
  re1 = /te[xs]t/;
  re2 = new RegExp('te[xs]t');
  re3 = new RegExp('te[xs]t');
  re3.compile();
  re4 = new RegExp();
  re4.compile('te[xs]t');
};
var suite = new Benchmark.Suite();

// add tests
suite.add('inline regex', function() {
  for (var i = 0; i < l; i++) {
    var r = /te[xs]t/.test(s);
  }
})
  .add('normal regex', function() {
  for (var i = 0; i < l; i++) {
    var r = re1.test(s);
  }
})
  .add('object regex', function() {
  for (var i = 0; i < l; i++) {
    var r = re2.test(s);
  }
})
  .add('compiled regex [1]', function() {
  for (var i = 0; i < l; i++) {
    var r = re3.test(s);
  }
})
  .add('compiled regex [2]', function() {
  for (var i = 0; i < l; i++) {
    var r = re4.test(s);
  }
})
// 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': false
});

$ node -v
v0.10.15
$ node ./benchmark-regex-compile.js
inline regex x 107 ops/sec ±0.46% (80 runs sampled)
normal regex x 114 ops/sec ±0.76% (75 runs sampled)
object regex x 114 ops/sec ±0.74% (75 runs sampled)
compiled regex [1] x 187 ops/sec ±1.72% (81 runs sampled)
compiled regex [2] x 114 ops/sec ±0.73% (75 runs sampled)
Fastest is compiled regex [1]