function hydrate()

in assets/js/vue.js [6354:6445]
81 lines of code
32 McCabe index (conditional complexity)

    function hydrate (elm, vnode, insertedVnodeQueue, inVPre) {
      var i;
      var tag = vnode.tag;
      var data = vnode.data;
      var children = vnode.children;
      inVPre = inVPre || (data && data.pre);
      vnode.elm = elm;

      if (isTrue(vnode.isComment) && isDef(vnode.asyncFactory)) {
        vnode.isAsyncPlaceholder = true;
        return true
      }
      // assert node match
      {
        if (!assertNodeMatch(elm, vnode, inVPre)) {
          return false
        }
      }
      if (isDef(data)) {
        if (isDef(i = data.hook) && isDef(i = i.init)) { i(vnode, true /* hydrating */); }
        if (isDef(i = vnode.componentInstance)) {
          // child component. it should have hydrated its own tree.
          initComponent(vnode, insertedVnodeQueue);
          return true
        }
      }
      if (isDef(tag)) {
        if (isDef(children)) {
          // empty element, allow client to pick up and populate children
          if (!elm.hasChildNodes()) {
            createChildren(vnode, children, insertedVnodeQueue);
          } else {
            // v-html and domProps: innerHTML
            if (isDef(i = data) && isDef(i = i.domProps) && isDef(i = i.innerHTML)) {
              if (i !== elm.innerHTML) {
                /* istanbul ignore if */
                if (typeof console !== 'undefined' &&
                  !hydrationBailed
                ) {
                  hydrationBailed = true;
                  console.warn('Parent: ', elm);
                  console.warn('server innerHTML: ', i);
                  console.warn('client innerHTML: ', elm.innerHTML);
                }
                return false
              }
            } else {
              // iterate and compare children lists
              var childrenMatch = true;
              var childNode = elm.firstChild;
              for (var i$1 = 0; i$1 < children.length; i$1++) {
                if (!childNode || !hydrate(childNode, children[i$1], insertedVnodeQueue, inVPre)) {
                  childrenMatch = false;
                  break
                }
                childNode = childNode.nextSibling;
              }
              // if childNode is not null, it means the actual childNodes list is
              // longer than the virtual children list.
              if (!childrenMatch || childNode) {
                /* istanbul ignore if */
                if (typeof console !== 'undefined' &&
                  !hydrationBailed
                ) {
                  hydrationBailed = true;
                  console.warn('Parent: ', elm);
                  console.warn('Mismatching childNodes vs. VNodes: ', elm.childNodes, children);
                }
                return false
              }
            }
          }
        }
        if (isDef(data)) {
          var fullInvoke = false;
          for (var key in data) {
            if (!isRenderedModule(key)) {
              fullInvoke = true;
              invokeCreateHooks(vnode, insertedVnodeQueue);
              break
            }
          }
          if (!fullInvoke && data['class']) {
            // ensure collecting deps for deep class bindings for future updates
            traverse(data['class']);
          }
        }
      } else if (elm.data !== vnode.text) {
        elm.data = vnode.text;
      }
      return true
    }