code: function(node, beforeCount, afterCount) {
          if (node) {
              return (this.text !== null) ? this.text.slice(Math.max(node.range[0] - (beforeCount || 0), 0),
                  node.range[1] + (afterCount || 0)) : null;
          }
          return this.text;
  
      }
docs: Gets the source code for the given node.
  @param {ASTNode=} node The AST node to get the text for.
  @param {int=} beforeCount The number of characters before the node to retrieve.
  @param {int=} afterCount The number of characters after the node to retrieve.
  @returns {string} The text representing the AST node.