code: function encodeString(string) {
  	//it actually accepts any kind of object as input
  	if (string === null) {
  		return values.NULL;
  	} else if (string === "") {
  		return values.EMPTY;
  	} else {//0 false undefined NaN will pass from here
  		return encodeURIComponent(string)
  		.replace(/%20/g, "+");
  	}
  }
docs: Encodes a string according to the ARI protocol.
  
  @param {String} string input
  @return {String} output
  @private