benchmark of String.lastIndexOf in Node.js

benchmark-lastindexof.js

var Benchmark = require('benchmark');
Benchmark.prototype.setup = function() {
  a = ["test"];
  for (var i = 0; i < 10000; i++) {
    a.push("some other stuff");
  }
  s = a.join();
};
var suite = new Benchmark.Suite();

// add tests
suite.add('existence', function() {
  var r1 = (s.lastIndexOf("test") === 0);
})
  .add('nonexistence', function() {
  var r2 = (s.lastIndexOf("not there") === 0);
})
  .add('existence start 0', function() {
  var r1 = (s.lastIndexOf("test", 0) === 0);
})
  .add('nonexistence start 0', function() {
  var r2 = (s.lastIndexOf("not there", 0) === 0);
})
  .add('existence indexOf', function() {
  var r1 = (s.indexOf("test") === 0);
})
  .add('nonexistence indexOf', function() {
  var r2 = (s.indexOf("not there") === 0);
})
// 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
});

existence x 2,044 ops/sec ±0.98% (78 runs sampled)
nonexistence x 6,596 ops/sec ±0.38% (84 runs sampled)
existence start 0 x 10,002,925 ops/sec ±0.64% (85 runs sampled)
nonexistence start 0 x 10,531,223 ops/sec ±0.73% (93 runs sampled)
existence indexOf x 10,945,037 ops/sec ±0.48% (89 runs sampled)
nonexistence indexOf x 11,610 ops/sec ±13.01% (66 runs sampled)
Fastest is existence indexOf