Javascript implementation of "Levenshtein Distance" algorithm.

levenshtein.js

// levenshtein('boo', 'bar') => 2
var levenshtein = function (a, b, al, bl) {
  var c = 1;
  al = typeof al === 'undefined' ? a.length : al;
  bl = typeof bl === 'undefined' ? b.length : bl;

  if (!al) return bl;
  if (!bl) return al;

  if (a[al - 1] === b[bl - 1]) {
    c = 0;
  }

  return Math.min(
    levenshtein(a, b, al - 1, bl) + 1,
    levenshtein(a, b, al, bl - 1) + 1,
    levenshtein(a, b, al - 1, bl - 1) + c
  );
};