code: function(alias, typeName){
      let template = this.resolve(typeName);
      if (!template){
        throw new ReferenceError('bad alias \'' + alias + '\': type \'' + typeName + '\' is undefined');
      }
      this.names[alias] = template;
    }
docs: Defines an typename alias.
  @param {String} alias
  @param {String} typeName - existing template type, may be a built-in type.