源碼大概5600-6600

  var creatingElmInVPre = 0;
  // 創(chuàng)建元素
  function createElm (
    vnode,
    insertedVnodeQueue,
    parentElm,
    refElm,
    nested,
    ownerArray,
    index
  ) {
    if (isDef(vnode.elm) && isDef(ownerArray)) {
      // This vnode was used in a previous render!
      // now it's used as a new node, overwriting its elm would cause
      // potential patch errors down the road when it's used as an insertion
      // reference node. Instead, we clone the node on-demand before creating
      // associated DOM element for it.
      // vnode克隆
      vnode = ownerArray[index] = cloneVNode(vnode);
    }
    // 是否嵌套
    vnode.isRootInsert = !nested; // for transition enter check
    // 如果使用了keep-live体捏，返回
    if (createComponent(vnode, insertedVnodeQueue, parentElm, refElm)) {
      return
    }

    var data = vnode.data;
    var children = vnode.children;
    var tag = vnode.tag;
    //創(chuàng)建dom,設(shè)置style,樣式
    if (isDef(tag)) {
      {
        if (data && data.pre) {
          creatingElmInVPre++;
        }
        if (isUnknownElement$$1(vnode, creatingElmInVPre)) {
          warn(
            'Unknown custom element: <' + tag + '> - did you ' +
            'register the component correctly? For recursive components, ' +
            'make sure to provide the "name" option.',
            vnode.context
          );
        }
      }

      vnode.elm = vnode.ns
        ? nodeOps.createElementNS(vnode.ns, tag)
        : nodeOps.createElement(tag, vnode);
      setScope(vnode);

      /* istanbul ignore if */
      // 生成子組件元素晚树，插入到父組件的元素里
      {
        createChildren(vnode, children, insertedVnodeQueue);
        if (isDef(data)) {
          invokeCreateHooks(vnode, insertedVnodeQueue);
        }
        insert(parentElm, vnode.elm, refElm);
      }

      if ("development" !== 'production' && data && data.pre) {
        creatingElmInVPre--;
      }
      // 是否是注釋
    } else if (isTrue(vnode.isComment)) {
      vnode.elm = nodeOps.createComment(vnode.text);
      insert(parentElm, vnode.elm, refElm);
    } else {
      // 是否是文字節(jié)點(diǎn)
      vnode.elm = nodeOps.createTextNode(vnode.text);
      insert(parentElm, vnode.elm, refElm);
    }
  }
  // 創(chuàng)建組件
  function createComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
    var i = vnode.data;
    if (isDef(i)) {
      var isReactivated = isDef(vnode.componentInstance) && i.keepAlive;
      if (isDef(i = i.hook) && isDef(i = i.init)) {
        i(vnode, false /* hydrating */, parentElm, refElm);
      }
      // after calling the init hook, if the vnode is a child component
      // it should've created a child instance and mounted it. the child
      // component also has set the placeholder vnode's elm.
      // in that case we can just return the element and be done.
      // 如果組件式使用了keep-live荷荤，并且是激活的塑径，生成和激活組件
      if (isDef(vnode.componentInstance)) {
        initComponent(vnode, insertedVnodeQueue);
        if (isTrue(isReactivated)) {
          reactivateComponent(vnode, insertedVnodeQueue, parentElm, refElm);
        }
        return true
      }
    }
  }

  function initComponent (vnode, insertedVnodeQueue) {
    if (isDef(vnode.data.pendingInsert)) {
      insertedVnodeQueue.push.apply(insertedVnodeQueue, vnode.data.pendingInsert);
      vnode.data.pendingInsert = null;
    }
    vnode.elm = vnode.componentInstance.$el;
    if (isPatchable(vnode)) {
      invokeCreateHooks(vnode, insertedVnodeQueue);
      setScope(vnode);
    } else {
      // empty component root.
      // skip all element-related modules except for ref (#3455)
      registerRef(vnode);
      // make sure to invoke the insert hook
      insertedVnodeQueue.push(vnode);
    }
  }

  function reactivateComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
    var i;
    // hack for #4339: a reactivated component with inner transition
    // does not trigger because the inner node's created hooks are not called
    // again. It's not ideal to involve module-specific logic in here but
    // there doesn't seem to be a better way to do it.
    var innerNode = vnode;
    while (innerNode.componentInstance) {
      innerNode = innerNode.componentInstance._vnode;
      if (isDef(i = innerNode.data) && isDef(i = i.transition)) {
        for (i = 0; i < cbs.activate.length; ++i) {
          cbs.activate[i](emptyNode, innerNode);
        }
        insertedVnodeQueue.push(innerNode);
        break
      }
    }
    // unlike a newly created component,
    // a reactivated keep-alive component doesn't insert itself
    insert(parentElm, vnode.elm, refElm);
  }

  function insert (parent, elm, ref$$1) {
    if (isDef(parent)) {
      if (isDef(ref$$1)) {
        if (ref$$1.parentNode === parent) {
          nodeOps.insertBefore(parent, elm, ref$$1);
        }
      } else {
        nodeOps.appendChild(parent, elm);
      }
    }
  }

  function createChildren (vnode, children, insertedVnodeQueue) {
    if (Array.isArray(children)) {
      {
        checkDuplicateKeys(children);
      }
      for (var i = 0; i < children.length; ++i) {
        createElm(children[i], insertedVnodeQueue, vnode.elm, null, true, children, i);
      }
    } else if (isPrimitive(vnode.text)) {
      nodeOps.appendChild(vnode.elm, nodeOps.createTextNode(String(vnode.text)));
    }
  }

  function isPatchable (vnode) {
    while (vnode.componentInstance) {
      vnode = vnode.componentInstance._vnode;
    }
    return isDef(vnode.tag)
  }

  function invokeCreateHooks (vnode, insertedVnodeQueue) {
    for (var i$1 = 0; i$1 < cbs.create.length; ++i$1) {
      cbs.create[i$1](emptyNode, vnode);
    }
    i = vnode.data.hook; // Reuse variable
    if (isDef(i)) {
      if (isDef(i.create)) { i.create(emptyNode, vnode); }
      if (isDef(i.insert)) { insertedVnodeQueue.push(vnode); }
    }
  }

  // set scope id attribute for scoped CSS.
  // this is implemented as a special case to avoid the overhead
  // of going through the normal attribute patching process.
  function setScope (vnode) {
    var i;
    if (isDef(i = vnode.fnScopeId)) {
      nodeOps.setStyleScope(vnode.elm, i);
    } else {
      var ancestor = vnode;
      while (ancestor) {
        if (isDef(i = ancestor.context) && isDef(i = i.$options._scopeId)) {
          nodeOps.setStyleScope(vnode.elm, i);
        }
        ancestor = ancestor.parent;
      }
    }
    // for slot content they should also get the scopeId from the host instance.
    if (isDef(i = activeInstance) &&
      i !== vnode.context &&
      i !== vnode.fnContext &&
      isDef(i = i.$options._scopeId)
    ) {
      nodeOps.setStyleScope(vnode.elm, i);
    }
  }

  function addVnodes (parentElm, refElm, vnodes, startIdx, endIdx, insertedVnodeQueue) {
    for (; startIdx <= endIdx; ++startIdx) {
      createElm(vnodes[startIdx], insertedVnodeQueue, parentElm, refElm, false, vnodes, startIdx);
    }
  }

  function invokeDestroyHook (vnode) {
    var i, j;
    var data = vnode.data;
    if (isDef(data)) {
      if (isDef(i = data.hook) && isDef(i = i.destroy)) { i(vnode); }
      for (i = 0; i < cbs.destroy.length; ++i) { cbs.destroy[i](vnode); }
    }
    if (isDef(i = vnode.children)) {
      for (j = 0; j < vnode.children.length; ++j) {
        invokeDestroyHook(vnode.children[j]);
      }
    }
  }

  function removeVnodes (parentElm, vnodes, startIdx, endIdx) {
    for (; startIdx <= endIdx; ++startIdx) {
      var ch = vnodes[startIdx];
      if (isDef(ch)) {
        if (isDef(ch.tag)) {
          removeAndInvokeRemoveHook(ch);
          invokeDestroyHook(ch);
        } else { // Text node
          removeNode(ch.elm);
        }
      }
    }
  }

  function removeAndInvokeRemoveHook (vnode, rm) {
    if (isDef(rm) || isDef(vnode.data)) {
      var i;
      var listeners = cbs.remove.length + 1;
      if (isDef(rm)) {
        // we have a recursively passed down rm callback
        // increase the listeners count
        rm.listeners += listeners;
      } else {
        // directly removing
        rm = createRmCb(vnode.elm, listeners);
      }
      // recursively invoke hooks on child component root node
      if (isDef(i = vnode.componentInstance) && isDef(i = i._vnode) && isDef(i.data)) {
        removeAndInvokeRemoveHook(i, rm);
      }
      for (i = 0; i < cbs.remove.length; ++i) {
        cbs.remove[i](vnode, rm);
      }
      if (isDef(i = vnode.data.hook) && isDef(i = i.remove)) {
        i(vnode, rm);
      } else {
        rm();
      }
    } else {
      removeNode(vnode.elm);
    }
  }

  function updateChildren (parentElm, oldCh, newCh, insertedVnodeQueue, removeOnly) {
    var oldStartIdx = 0;
    var newStartIdx = 0;
    var oldEndIdx = oldCh.length - 1;
    var oldStartVnode = oldCh[0];
    var oldEndVnode = oldCh[oldEndIdx];
    var newEndIdx = newCh.length - 1;
    var newStartVnode = newCh[0];
    var newEndVnode = newCh[newEndIdx];
    var oldKeyToIdx, idxInOld, vnodeToMove, refElm;

    // removeOnly is a special flag used only by <transition-group>
    // to ensure removed elements stay in correct relative positions
    // during leaving transitions
    var canMove = !removeOnly;

    {
      checkDuplicateKeys(newCh);
    }

    while (oldStartIdx <= oldEndIdx && newStartIdx <= newEndIdx) {
      if (isUndef(oldStartVnode)) {
        oldStartVnode = oldCh[++oldStartIdx]; // Vnode has been moved left
      } else if (isUndef(oldEndVnode)) {
        oldEndVnode = oldCh[--oldEndIdx];
      } else if (sameVnode(oldStartVnode, newStartVnode)) {
        patchVnode(oldStartVnode, newStartVnode, insertedVnodeQueue);
        oldStartVnode = oldCh[++oldStartIdx];
        newStartVnode = newCh[++newStartIdx];
      } else if (sameVnode(oldEndVnode, newEndVnode)) {
        patchVnode(oldEndVnode, newEndVnode, insertedVnodeQueue);
        oldEndVnode = oldCh[--oldEndIdx];
        newEndVnode = newCh[--newEndIdx];
      } else if (sameVnode(oldStartVnode, newEndVnode)) { // Vnode moved right
        patchVnode(oldStartVnode, newEndVnode, insertedVnodeQueue);
        canMove && nodeOps.insertBefore(parentElm, oldStartVnode.elm, nodeOps.nextSibling(oldEndVnode.elm));
        oldStartVnode = oldCh[++oldStartIdx];
        newEndVnode = newCh[--newEndIdx];
      } else if (sameVnode(oldEndVnode, newStartVnode)) { // Vnode moved left
        patchVnode(oldEndVnode, newStartVnode, insertedVnodeQueue);
        canMove && nodeOps.insertBefore(parentElm, oldEndVnode.elm, oldStartVnode.elm);
        oldEndVnode = oldCh[--oldEndIdx];
        newStartVnode = newCh[++newStartIdx];
      } else {
        if (isUndef(oldKeyToIdx)) { oldKeyToIdx = createKeyToOldIdx(oldCh, oldStartIdx, oldEndIdx); }
        idxInOld = isDef(newStartVnode.key)
          ? oldKeyToIdx[newStartVnode.key]
          : findIdxInOld(newStartVnode, oldCh, oldStartIdx, oldEndIdx);
        if (isUndef(idxInOld)) { // New element
          createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm, false, newCh, newStartIdx);
        } else {
          vnodeToMove = oldCh[idxInOld];
          if (sameVnode(vnodeToMove, newStartVnode)) {
            patchVnode(vnodeToMove, newStartVnode, insertedVnodeQueue);
            oldCh[idxInOld] = undefined;
            canMove && nodeOps.insertBefore(parentElm, vnodeToMove.elm, oldStartVnode.elm);
          } else {
            // same key but different element. treat as new element
            createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm, false, newCh, newStartIdx);
          }
        }
        newStartVnode = newCh[++newStartIdx];
      }
    }
    if (oldStartIdx > oldEndIdx) {
      refElm = isUndef(newCh[newEndIdx + 1]) ? null : newCh[newEndIdx + 1].elm;
      addVnodes(parentElm, refElm, newCh, newStartIdx, newEndIdx, insertedVnodeQueue);
    } else if (newStartIdx > newEndIdx) {
      removeVnodes(parentElm, oldCh, oldStartIdx, oldEndIdx);
    }
  }
  // 檢查key是否重復(fù)
  function checkDuplicateKeys (children) {
    var seenKeys = {};
    for (var i = 0; i < children.length; i++) {
      var vnode = children[i];
      var key = vnode.key;
      if (isDef(key)) {
        if (seenKeys[key]) {
          warn(
            ("Duplicate keys detected: '" + key + "'. This may cause an update error."),
            vnode.context
          );
        } else {
          seenKeys[key] = true;
        }
      }
    }
  }
  // 找到node的index
  function findIdxInOld (node, oldCh, start, end) {
    for (var i = start; i < end; i++) {
      var c = oldCh[i];
      if (isDef(c) && sameVnode(node, c)) { return i }
    }
  }

  function patchVnode (oldVnode, vnode, insertedVnodeQueue, removeOnly) {
    if (oldVnode === vnode) {
      return
    }

    var elm = vnode.elm = oldVnode.elm;

    if (isTrue(oldVnode.isAsyncPlaceholder)) {
      if (isDef(vnode.asyncFactory.resolved)) {
        hydrate(oldVnode.elm, vnode, insertedVnodeQueue);
      } else {
        vnode.isAsyncPlaceholder = true;
      }
      return
    }

    // reuse element for static trees.
    // note we only do this if the vnode is cloned -
    // if the new node is not cloned it means the render functions have been
    // reset by the hot-reload-api and we need to do a proper re-render.
    if (isTrue(vnode.isStatic) &&
      isTrue(oldVnode.isStatic) &&
      vnode.key === oldVnode.key &&
      (isTrue(vnode.isCloned) || isTrue(vnode.isOnce))
    ) {
      vnode.componentInstance = oldVnode.componentInstance;
      return
    }

    var i;
    var data = vnode.data;
    if (isDef(data) && isDef(i = data.hook) && isDef(i = i.prepatch)) {
      i(oldVnode, vnode);
    }

    var oldCh = oldVnode.children;
    var ch = vnode.children;
    if (isDef(data) && isPatchable(vnode)) {
      for (i = 0; i < cbs.update.length; ++i) { cbs.update[i](oldVnode, vnode); }
      if (isDef(i = data.hook) && isDef(i = i.update)) { i(oldVnode, vnode); }
    }
    if (isUndef(vnode.text)) {
      if (isDef(oldCh) && isDef(ch)) {
        if (oldCh !== ch) { updateChildren(elm, oldCh, ch, insertedVnodeQueue, removeOnly); }
      } else if (isDef(ch)) {
        if (isDef(oldVnode.text)) { nodeOps.setTextContent(elm, ''); }
        addVnodes(elm, null, ch, 0, ch.length - 1, insertedVnodeQueue);
      } else if (isDef(oldCh)) {
        removeVnodes(elm, oldCh, 0, oldCh.length - 1);
      } else if (isDef(oldVnode.text)) {
        nodeOps.setTextContent(elm, '');
      }
    } else if (oldVnode.text !== vnode.text) {
      nodeOps.setTextContent(elm, vnode.text);
    }
    if (isDef(data)) {
      if (isDef(i = data.hook) && isDef(i = i.postpatch)) { i(oldVnode, vnode); }
    }
  }

  function invokeInsertHook (vnode, queue, initial) {
    // delay insert hooks for component root nodes, invoke them after the
    // element is really inserted
    if (isTrue(initial) && isDef(vnode.parent)) {
      vnode.parent.data.pendingInsert = queue;
    } else {
      for (var i = 0; i < queue.length; ++i) {
        queue[i].data.hook.insert(queue[i]);
      }
    }
  }

  var hydrationBailed = false;
  // list of modules that can skip create hook during hydration because they
  // are already rendered on the client or has no need for initialization
  // Note: style is excluded because it relies on initial clone for future
  // deep updates (#7063).
  var isRenderedModule = makeMap('attrs,class,staticClass,staticStyle,key');

  // Note: this is a browser-only function so we can assume elms are DOM nodes.
  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 ("development" !== 'production' &&
                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 ("development" !== 'production' &&
                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
  }

  function assertNodeMatch (node, vnode, inVPre) {
    if (isDef(vnode.tag)) {
      return vnode.tag.indexOf('vue-component') === 0 || (
        !isUnknownElement$$1(vnode, inVPre) &&
        vnode.tag.toLowerCase() === (node.tagName && node.tagName.toLowerCase())
      )
    } else {
      return node.nodeType === (vnode.isComment ? 8 : 3)
    }
  }

  return function patch (oldVnode, vnode, hydrating, removeOnly, parentElm, refElm) {
    if (isUndef(vnode)) {
      if (isDef(oldVnode)) { invokeDestroyHook(oldVnode); }
      return
    }

    var isInitialPatch = false;
    var insertedVnodeQueue = [];

    if (isUndef(oldVnode)) {
      // empty mount (likely as component), create new root element
      isInitialPatch = true;
      createElm(vnode, insertedVnodeQueue, parentElm, refElm);
    } else {
      var isRealElement = isDef(oldVnode.nodeType);
      if (!isRealElement && sameVnode(oldVnode, vnode)) {
        // patch existing root node
        patchVnode(oldVnode, vnode, insertedVnodeQueue, removeOnly);
      } else {
        if (isRealElement) {
          // mounting to a real element
          // check if this is server-rendered content and if we can perform
          // a successful hydration.
          if (oldVnode.nodeType === 1 && oldVnode.hasAttribute(SSR_ATTR)) {
            oldVnode.removeAttribute(SSR_ATTR);
            hydrating = true;
          }
          if (isTrue(hydrating)) {
            if (hydrate(oldVnode, vnode, insertedVnodeQueue)) {
              invokeInsertHook(vnode, insertedVnodeQueue, true);
              return oldVnode
            } else {
              warn(
                'The client-side rendered virtual DOM tree is not matching ' +
                'server-rendered content. This is likely caused by incorrect ' +
                'HTML markup, for example nesting block-level elements inside ' +
                '<p>, or missing <tbody>. Bailing hydration and performing ' +
                'full client-side render.'
              );
            }
          }
          // either not server-rendered, or hydration failed.
          // create an empty node and replace it
          oldVnode = emptyNodeAt(oldVnode);
        }

        // replacing existing element
        var oldElm = oldVnode.elm;
        var parentElm$1 = nodeOps.parentNode(oldElm);

        // create new node
        createElm(
          vnode,
          insertedVnodeQueue,
          // extremely rare edge case: do not insert if old element is in a
          // leaving transition. Only happens when combining transition +
          // keep-alive + HOCs. (#4590)
          oldElm._leaveCb ? null : parentElm$1,
          nodeOps.nextSibling(oldElm)
        );

        // update parent placeholder node element, recursively
        if (isDef(vnode.parent)) {
          var ancestor = vnode.parent;
          var patchable = isPatchable(vnode);
          while (ancestor) {
            for (var i = 0; i < cbs.destroy.length; ++i) {
              cbs.destroy[i](ancestor);
            }
            ancestor.elm = vnode.elm;
            if (patchable) {
              for (var i$1 = 0; i$1 < cbs.create.length; ++i$1) {
                cbs.create[i$1](emptyNode, ancestor);
              }
              // #6513
              // invoke insert hooks that may have been merged by create hooks.
              // e.g. for directives that uses the "inserted" hook.
              var insert = ancestor.data.hook.insert;
              if (insert.merged) {
                // start at index 1 to avoid re-invoking component mounted hook
                for (var i$2 = 1; i$2 < insert.fns.length; i$2++) {
                  insert.fns[i$2]();
                }
              }
            } else {
              registerRef(ancestor);
            }
            ancestor = ancestor.parent;
          }
        }

        // destroy old node
        if (isDef(parentElm$1)) {
          removeVnodes(parentElm$1, [oldVnode], 0, 0);
        } else if (isDef(oldVnode.tag)) {
          invokeDestroyHook(oldVnode);
        }
      }
    }

    invokeInsertHook(vnode, insertedVnodeQueue, isInitialPatch);
    return vnode.elm
  }
}

/*  */
// 指令三個方法
var directives = {
  create: updateDirectives,
  update: updateDirectives,
  destroy: function unbindDirectives (vnode) {
    updateDirectives(vnode, emptyNode);
  }
}
// 跟新指令，新舊vnode對比
function updateDirectives (oldVnode, vnode) {
  if (oldVnode.data.directives || vnode.data.directives) {
    _update(oldVnode, vnode);
  }
}
// 
function _update (oldVnode, vnode) {
  var isCreate = oldVnode === emptyNode;
  var isDestroy = vnode === emptyNode;
  var oldDirs = normalizeDirectives$1(oldVnode.data.directives, oldVnode.context);
  var newDirs = normalizeDirectives$1(vnode.data.directives, vnode.context);

  var dirsWithInsert = [];
  var dirsWithPostpatch = [];

  var key, oldDir, dir;
  for (key in newDirs) {
    oldDir = oldDirs[key];
    dir = newDirs[key];
    if (!oldDir) {
      // new directive, bind
      callHook$1(dir, 'bind', vnode, oldVnode);
      if (dir.def && dir.def.inserted) {
        dirsWithInsert.push(dir);
      }
    } else {
      // existing directive, update
      dir.oldValue = oldDir.value;
      callHook$1(dir, 'update', vnode, oldVnode);
      if (dir.def && dir.def.componentUpdated) {
        dirsWithPostpatch.push(dir);
      }
    }
  }

  if (dirsWithInsert.length) {
    var callInsert = function () {
      for (var i = 0; i < dirsWithInsert.length; i++) {
        callHook$1(dirsWithInsert[i], 'inserted', vnode, oldVnode);
      }
    };
    if (isCreate) {
      mergeVNodeHook(vnode, 'insert', callInsert);
    } else {
      callInsert();
    }
  }

  if (dirsWithPostpatch.length) {
    mergeVNodeHook(vnode, 'postpatch', function () {
      for (var i = 0; i < dirsWithPostpatch.length; i++) {
        callHook$1(dirsWithPostpatch[i], 'componentUpdated', vnode, oldVnode);
      }
    });
  }

  if (!isCreate) {
    for (key in oldDirs) {
      if (!newDirs[key]) {
        // no longer present, unbind
        callHook$1(oldDirs[key], 'unbind', oldVnode, oldVnode, isDestroy);
      }
    }
  }
}

var emptyModifiers = Object.create(null);
// 生成指令集合
function normalizeDirectives$1 (
  dirs,
  vm
) {
  var res = Object.create(null);
  if (!dirs) {
    // $flow-disable-line
    return res
  }
  var i, dir;
  for (i = 0; i < dirs.length; i++) {
    dir = dirs[i];
    if (!dir.modifiers) {
      // $flow-disable-line
      dir.modifiers = emptyModifiers;
    }
    res[getRawDirName(dir)] = dir;
    dir.def = resolveAsset(vm.$options, 'directives', dir.name, true);
  }
  // $flow-disable-line
  return res
}

function getRawDirName (dir) {
  return dir.rawName || ((dir.name) + "." + (Object.keys(dir.modifiers || {}).join('.')))
}
//執(zhí)行指令的周期
function callHook$1 (dir, hook, vnode, oldVnode, isDestroy) {
  var fn = dir.def && dir.def[hook];
  if (fn) {
    try {
      fn(vnode.elm, dir, vnode, oldVnode, isDestroy);
    } catch (e) {
      handleError(e, vnode.context, ("directive " + (dir.name) + " " + hook + " hook"));
    }
  }
}

var baseModules = [
  ref,
  directives
]

/*  */
// 跟新屬性，新舊對比
function updateAttrs (oldVnode, vnode) {
  var opts = vnode.componentOptions;
  if (isDef(opts) && opts.Ctor.options.inheritAttrs === false) {
    return
  }
  if (isUndef(oldVnode.data.attrs) && isUndef(vnode.data.attrs)) {
    return
  }
  var key, cur, old;
  var elm = vnode.elm;
  var oldAttrs = oldVnode.data.attrs || {};
  var attrs = vnode.data.attrs || {};
  // clone observed objects, as the user probably wants to mutate it
  if (isDef(attrs.__ob__)) {
    attrs = vnode.data.attrs = extend({}, attrs);
  }

  for (key in attrs) {
    cur = attrs[key];
    old = oldAttrs[key];
    if (old !== cur) {
      setAttr(elm, key, cur);
    }
  }
  // #4391: in IE9, setting type can reset value for input[type=radio]
  // #6666: IE/Edge forces progress value down to 1 before setting a max
  /* istanbul ignore if */
  if ((isIE || isEdge) && attrs.value !== oldAttrs.value) {
    setAttr(elm, 'value', attrs.value);
  }
  for (key in oldAttrs) {
    if (isUndef(attrs[key])) {
      if (isXlink(key)) {
        elm.removeAttributeNS(xlinkNS, getXlinkProp(key));
      } else if (!isEnumeratedAttr(key)) {
        elm.removeAttribute(key);
      }
    }
  }
}

function setAttr (el, key, value) {
  // 設(shè)置屬性有-，直接設(shè)置
  if (el.tagName.indexOf('-') > -1) {
    baseSetAttr(el, key, value);
  } else if (isBooleanAttr(key)) {
    // 如果是布爾類型
    // set attribute for blank value
    // e.g. <option disabled>Select one</option>
    if (isFalsyAttrValue(value)) {
      el.removeAttribute(key);
    } else {
      // technically allowfullscreen is a boolean attribute for <iframe>,
      // but Flash expects a value of "true" when used on <embed> tag
      value = key === 'allowfullscreen' && el.tagName === 'EMBED'
        ? 'true'
        : key;
      el.setAttribute(key, value);
    }
    // 枚舉的key
  } else if (isEnumeratedAttr(key)) {
    el.setAttribute(key, isFalsyAttrValue(value) || value === 'false' ? 'false' : 'true');
    // xlink
  } else if (isXlink(key)) {
    if (isFalsyAttrValue(value)) {
      el.removeAttributeNS(xlinkNS, getXlinkProp(key));
    } else {
      el.setAttributeNS(xlinkNS, key, value);
    }
  } else {
    //其它
    baseSetAttr(el, key, value);
  }
}

function baseSetAttr (el, key, value) {
  // 不是合法的屬性移除
  if (isFalsyAttrValue(value)) {
    el.removeAttribute(key);
  // 設(shè)置元素屬性
  } else {
    // #7138: IE10 & 11 fires input event when setting placeholder on
    // <textarea>... block the first input event and remove the blocker
    // immediately.
    /* istanbul ignore if */
    // 如果是textarea，屬性是placeholder,其他的監(jiān)聽函數(shù)停止監(jiān)聽
    if (
      isIE && !isIE9 &&
      el.tagName === 'TEXTAREA' &&
      key === 'placeholder' && !el.__ieph
    ) {
      var blocker = function (e) {
        e.stopImmediatePropagation();
        el.removeEventListener('input', blocker);
      };
      el.addEventListener('input', blocker);
      // $flow-disable-line
      el.__ieph = true; /* IE placeholder patched */
    }
    el.setAttribute(key, value);
  }
}
// 屬性集合
var attrs = {
  create: updateAttrs,
  update: updateAttrs
}

/*  */

function updateClass (oldVnode, vnode) {
  var el = vnode.elm;
  var data = vnode.data;
  var oldData = oldVnode.data;
  if (
    isUndef(data.staticClass) &&
    isUndef(data.class) && (
      isUndef(oldData) || (
        isUndef(oldData.staticClass) &&
        isUndef(oldData.class)
      )
    )
  ) {
    return
  }
  // 類集合
  var cls = genClassForVnode(vnode);

  // handle transition classes
  // 動畫的類集合
  var transitionClass = el._transitionClasses;
  // 合并
  if (isDef(transitionClass)) {
    cls = concat(cls, stringifyClass(transitionClass));
  }

  // set the class
  // 設(shè)置屬性
  if (cls !== el._prevClass) {
    el.setAttribute('class', cls);
    el._prevClass = cls;
  }
}
// 類的集合
var klass = {
  create: updateClass,
  update: updateClass
}