lib/index.js
function cleanAlphabet(alphabet) {
    return alphabet.split('').filter(function (item, pos, self) {
      return self.indexOf(item) === pos;
    }).join('');
  }
function cleanAlphabet(alphabet) {
    return alphabet.split('').filter(function (item, pos, self) {
      return self.indexOf(item) === pos;
    }).join('');
  }
function cleanAlphabet ( alphabet ) { return alphabet . split ( '' ) . filter ( function ( item , pos , self ) { return self . indexOf ( item ) === pos ; } ) . join ( '' ) ; }
remove duplicates from alphabets
remove duplicates from alphabets