regex_vs_lowercase

var Benchmark = require('benchmark');

var suite = new Benchmark.Suite;

// add tests
suite.add('lowercase', function() {
  let input = 'ai';
  let dictionary = ['airplane','airport','apple','ball'];

  var clean_str = input.replace(/[^a-z]+/gi,'').toLowerCase();

  let res = dictionary
    .filter(x => x.toLowerCase().startsWith(clean_str))
    .slice(0,5);  
})
.add('regex', function() {
  let input = 'ai';
  let dictionary = ['airplane','airport','apple','ball'];

  var r = new RegExp('^' + input.replace(/[^a-z]/gi,''), 'i');

  let res = dictionary.filter(function(w){ return r.test(w); }).slice(0, 5);
})
.on('cycle', function(event) {
  console.log(String(event.target));
})
.on('complete', function() {
  console.log(this);
})
.run({ 'async': true });