code: function (sourceBuffer, aNode, owner) {
          // inner content
          if (aNode.tagName === 'textarea') {
              var valueProp = getANodeProp(aNode, 'value');
              if (valueProp) {
                  sourceBuffer.joinRaw('escapeHTML('
                      + compileExprSource.expr(valueProp.expr)
                      + ')'
                  );
              }
  
              return;
          }
  
          var htmlDirective = aNode.directives.html;
          if (htmlDirective) {
              sourceBuffer.joinExpr(htmlDirective.value);
          }
          else {
              /* eslint-disable no-use-before-define */
              each(aNode.children, function (aNodeChild) {
                  aNodeCompiler.compile(aNodeChild, sourceBuffer, owner);
              });
              /* eslint-enable no-use-before-define */
          }
      }
docs: 编译元素内容
  
  @param {CompileSourceBuffer} sourceBuffer 编译源码的中间buffer
  @param {ANode} aNode 元素的抽象节点信息
  @param {Component} owner 所属组件实例环境