Is Palindrome?

JavaScript performance comparison

Revision 7 of this test case created by KC

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) {
  var middle = Math.floor(str.length / 2),
  l = str.length;
  for (var i=0; i<middle; i++) {
    if (str.charAt(i) !== str.charAt(l-i-1)) return false;
  }
  return true;
}

function f4(str) {
  for (var i = 0; i < str.length/2 << 0; i++) {
    if (str.charAt(i) !== str.charAt(str.length-i-1)) {
      return false;
    }
  }
  return true;
}
</script>
<script>
Benchmark.prototype.setup = function() {
    var str1 = "abcdefghijklmnopqrstuvwxyzzyxwvutsrqponmlkjihgfedcba";
    var str2 = "abcdefghijklmnopqrstuvwxyzyxwvutsrqponmlkjihgfedcba";
    var str3 = "abcdefghijklmnopqrstuvwxyzZyxwvutsrqponmlkjihgfedcba";
};
</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;
pending…
While loop character comparison
f2(str1) === true;
f2(str2) === true;
f2(str3) === false;
pending…
For loop
f3(str1) === true;
f3(str2) === true;
f3(str3) === false;
pending…
For loop improved
f4(str1) === true;
f4(str2) === true;
f4(str3) === false;
pending…

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Revisions

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