Is Palindrome?

JavaScript performance comparison

Revision 5 of this test case created by pixshatterer

Info

a silly test of palindrome testing techniques

Preparation code

<script>
  function f1(str) {
    return str === str.split('').reverse().join('');
  }

  function f2(str) {
    var i = str.length - 1;
    var k = 0;
    while (i > k) {
      if (str.charAt(k++) !== str.charAt(i--)) return false;
    }
    return true;
  }
 
  function f3(str) {
    return str.substring(0, Math.floor(str.length / 2)) == (str.substring(Math.ceil(str.length / 2)).split('').reverse().join(''));
  }

function isPalindrome(str) {
        var halfLimit, mirrorStr,
                SPECIAL_CHARS_EXP = /[áéíóú\W]/gi;
                SPECIAL_CHARS_DICT = {
                        'á' : 'a',
                        'é' : 'e',
                        'í' : 'i',
                        'ó' : 'o',
                        'ú' : 'u'
                };
               
        str = str.toLowerCase().replace(SPECIAL_CHARS_EXP,function(matchedChar){
                return SPECIAL_CHARS_DICT[matchedChar]? SPECIAL_CHARS_DICT[matchedChar] : '';
        });

        halfLimit = str.length / 2 + (str.length % 2),
        mirrorStr = str.substr(halfLimit).match(/\w/g).reverse().join('');
       
        return str.indexOf(mirrorStr) === 0;
}
</script>
<script>
Benchmark.prototype.setup = function() {
    var str1 = "abcdefghijklmnopqrstuvwxyzzyxwvutsrqponmlkjihgfedcba";
    var str2 = "abcdefghijklmnopqrstuvwxyzyxwvutsrqponmlkjihgfedcba";
    var str3 = "abcdefghijklmnopqrstuvwxyzZyxwvutsrqponmlkjihgfedcba";
    var str4 = "Átale, demoníaco Caín, o me delata.";
    var str5 = "¿Acaso hubo búhos acá?";
};
</script>

Test runner

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Testing in unknown unknown
Test Ops/sec
native strip reverse
f1(str1) === true;
f1(str2) === true;
f1(str3) === false;
f1(str4) === true;
f1(str5) === true;
pending…
for-loop character comparison
f2(str1) === true;
f2(str2) === true;
f2(str3) === false;
f2(str4) === true;
f2(str5) === true;
pending…
reverse half
f3(str1) === true;
f3(str2) === true;
f3(str3) === false;
f3(str4) === true;
f3(str5) === true;
pending…
checking chars
isPalindrome(str1) === true;
isPalindrome(str2) === true;
isPalindrome(str3) === false;
isPalindrome(str4) === true;
isPalindrome(str5) === true;
pending…

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