code: function (node) {
      switch (node.nodeType) {
        case NODE_TYPE.ELEMENT:
          this._beginVisitElement(node);
          break;
  
        case NODE_TYPE.TEXT:
          this._visitText(node);
          break;
  
        case NODE_TYPE.COMMENT:
          this._visitComment(node);
          break;
  
        default:
          console.warn('Unrecognised node type: ' + node.nodeType);
      }
    }
docs: Handle pre-visit behaviour for the specified node.
  
  @param {Node} node