primer letra mayuscula Capital Letter

ex.ts

primeraLetraMayuscula( str )
  {
      let pieces = str.split(" ");
      for ( let i = 0; i < pieces.length; i++ )
      {
          let j = pieces[i].charAt(0).toUpperCase();
          pieces[i] = j + pieces[i].substr(1).toLowerCase();
      }
      return pieces.join(" ");
  }