Implementation of the Levenshtein distance algorithm in javascript.

levenshtein.js

function difference(s, t) {
  if ( s === t ) {
    return 0;
  }
  
  if ( s.length === 0 ) {
    return s.length;
  }
  
  if ( t.length === 0 ) {
    return t.length;
  }
  
  var v0 = new Array(t.length + 1);
  var v1 = new Array(t.length + 1);
  
  for (var i = 0; i < v0.length; i++) {
    v0[i] = i;
  }
  
  for (var i = 0; i < s.length; i++) {
    v1[0] = i + 1;
    
    for (var j = 0; j < t.length; j++) {
      var cost = s[i] === t[j] ? 0 : 1;
      v1[j + 1] = Math.min(v1[j] + 1, v0[j + 1], v0[j] + cost);
    }
    
    for (var j = 0; j < v0.length; j++) {
      v0[j] = v1[j];
    }
  }
  
  return v1[t.length];
}