Snap.svg class add, remove, toggle, has handling

// Large swatches copied from jQuery.
//    "cargo-culting, makes me happy"  Don Ho we love you!!

Snap.plugin(function (Snap, Element ) {

  // Used for splitting on whitespace
  var core_rnotwhite = /\S+/g,

      rclass = /[\t\r\n\f]/g,

  // Make sure we trim BOM and NBSP (here's looking at you, Safari 5.0 and IE)
      rtrim = /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g;

  function trim( text ) {
        return text == null ?  
          "" :
          ( text + "" ).replace( rtrim, "" );
  }


  Element.prototype.addClass = function addClass( value ) {
    var el = this;

    var classes, current, original, clazz, j;

    if ( typeof value === "string" && value ) {
      classes = ( value || "" ).match( core_rnotwhite ) || [];

      current = original = el.attr('class');
      current = current ? (" " + current + " ").replace(rclass, " ") :  " ";

      j = 0;
      while ( (clazz = classes[j++]) ) {
        if ( current.indexOf( " " + clazz + " " ) < 0 ) {
            current += clazz + " ";
        }
      }

      current = trim( current );
      if ( original !== current )
        el.attr('class', current);
    }

    return el;
  };

  Element.prototype.removeClass = function removeClass( value ) {
    var el = this;

    var classes, current, original, clazz, j;

    if ( arguments.length === 0 || typeof value === "string" && value ) {

      classes = ( value || "" ).match( core_rnotwhite ) || [];

      current = original = el.attr('class');
      current = current ? (" " + current + " ").replace(rclass, " ") :  " ";

      j = 0;
      while ( (clazz = classes[j++]) ) {
        // Remove *all* instances
        while ( current.indexOf( " " + clazz + " " ) >= 0 ) {
            current = current.replace( " " + clazz + " ", " " );
        }
      }

      current = value ? trim( current ) : "";
      if ( original !== current )
        el.attr('class', current);
    }

    return el;
  };


  Element.prototype.toggleClass = function toggleClass( value, stateVal ) {

    if ( typeof stateVal === "boolean" && typeof value === "string" ) {
      return stateVal ? this.addClass( value ) : this.removeClass( value );
    }

    if ( typeof value === "string" && value ) {

      var classes = value.match( core_rnotwhite ) || [],
          i = 0;

      while ( (className = classes[ i++ ]) ) {
        if ( this.hasClass( className ) ) {
            this.removeClass( className );
        } else {
            this.addClass( className );
        }
      }
    }

    return this;
  };


  Element.prototype.hasClass = function hasClass( className ) {

    className = " " + className + " ";

    var current = this.attr('class');
    current = current ? (" " + current + " ").replace(rclass, " ") :  " ";

    return  current.indexOf( className ) >= 0;
  };

});