pwnt.be

Another addition I would like to see in MooTools—or, better yet, ECMAScript in general—is the equivalent of Java’s String.equalsIgnoreCase(String) function. Sure, a first implementation is trivial:

String.extend({
  'equalsIgnoreCase': function(str) {
    return (this.toLowerCase() == str.toLowerCase()
      && this.toUpperCase() == str.toUpperCase());
  }
});

… but if you want it to be a little more efficient, you’ll avoid inspecting both strings in their entirety first and use String.charAt(int) instead. If your motto is ‘Code is Poetry’, you’ll end up with something like …

String.extend({
  'equalsIgnoreCase': function(str) {
    var i = -1;
    if (this.length == str.length) {
      i = 0;
      while (i < this.length
      && this.charAt(i).toLowerCase() == str.charAt(i).toLowerCase()
      && this.charAt(i).toUpperCase() == str.charAt(i).toUpperCase()) {
        i++;
      }
    }
    return (i == this.length);
  }
});

Since ECMAScript is weakly typed and doesn’t have a Character class like Java does, the actual comparison still uses string functions. I wonder how much this influences the algorithm’s performance.

Update: I added the String.toUpperCase() calls, because Java’s implementation has them too. I’m no expert when it comes to international characters.