vue
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Reactive, component-oriented view layer for modern web interfaces.
631 lines (586 loc) • 21.4 kB
JavaScript
/**
* Virtual DOM patching algorithm based on Snabbdom by
* Simon Friis Vindum (@paldepind)
* Licensed under the MIT License
* https://github.com/paldepind/snabbdom/blob/master/LICENSE
*
* modified by Evan You (@yyx990803)
*
/*
* Not type-checking this because this file is perf-critical and the cost
* of making flow understand it is not worth it.
*/
import config from '../config'
import VNode from './vnode'
import { makeMap, isPrimitive, warn } from '../util/index'
import { activeInstance } from '../instance/lifecycle'
import { registerRef } from './modules/ref'
export const emptyNode = new VNode('', {}, [])
const hooks = ['create', 'activate', 'update', 'remove', 'destroy']
function isUndef (s) {
return s == null
}
function isDef (s) {
return s != null
}
function sameVnode (vnode1, vnode2) {
return (
vnode1.key === vnode2.key &&
vnode1.tag === vnode2.tag &&
vnode1.isComment === vnode2.isComment &&
!vnode1.data === !vnode2.data
)
}
function createKeyToOldIdx (children, beginIdx, endIdx) {
let i, key
const map = {}
for (i = beginIdx; i <= endIdx; ++i) {
key = children[i].key
if (isDef(key)) map[key] = i
}
return map
}
export function createPatchFunction (backend) {
let i, j
const cbs = {}
const { modules, nodeOps } = backend
for (i = 0; i < hooks.length; ++i) {
cbs[hooks[i]] = []
for (j = 0; j < modules.length; ++j) {
if (modules[j][hooks[i]] !== undefined) cbs[hooks[i]].push(modules[j][hooks[i]])
}
}
function emptyNodeAt (elm) {
return new VNode(nodeOps.tagName(elm).toLowerCase(), {}, [], undefined, elm)
}
function createRmCb (childElm, listeners) {
function remove () {
if (--remove.listeners === 0) {
removeNode(childElm)
}
}
remove.listeners = listeners
return remove
}
function removeNode (el) {
const parent = nodeOps.parentNode(el)
// element may have already been removed due to v-html / v-text
if (parent) {
nodeOps.removeChild(parent, el)
}
}
let inPre = 0
function createElm (vnode, insertedVnodeQueue, parentElm, refElm, nested) {
vnode.isRootInsert = !nested // for transition enter check
if (createComponent(vnode, insertedVnodeQueue, parentElm, refElm)) {
return
}
const data = vnode.data
const children = vnode.children
const tag = vnode.tag
if (isDef(tag)) {
if (process.env.NODE_ENV !== 'production') {
if (data && data.pre) {
inPre++
}
if (
!inPre &&
!vnode.ns &&
!(config.ignoredElements.length && config.ignoredElements.indexOf(tag) > -1) &&
config.isUnknownElement(tag)
) {
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 */
if (__WEEX__) {
// in Weex, the default insertion order is parent-first.
// List items can be optimized to use children-first insertion
// with append="tree".
const appendAsTree = data && data.appendAsTree
if (!appendAsTree) {
if (isDef(data)) {
invokeCreateHooks(vnode, insertedVnodeQueue)
}
insert(parentElm, vnode.elm, refElm)
}
createChildren(vnode, children, insertedVnodeQueue)
if (appendAsTree) {
if (isDef(data)) {
invokeCreateHooks(vnode, insertedVnodeQueue)
}
insert(parentElm, vnode.elm, refElm)
}
} else {
createChildren(vnode, children, insertedVnodeQueue)
if (isDef(data)) {
invokeCreateHooks(vnode, insertedVnodeQueue)
}
insert(parentElm, vnode.elm, refElm)
}
if (process.env.NODE_ENV !== 'production' && data && data.pre) {
inPre--
}
} else if (vnode.isComment) {
vnode.elm = nodeOps.createComment(vnode.text)
insert(parentElm, vnode.elm, refElm)
} else {
vnode.elm = nodeOps.createTextNode(vnode.text)
insert(parentElm, vnode.elm, refElm)
}
}
function createComponent (vnode, insertedVnodeQueue, parentElm, refElm) {
let i = vnode.data
if (isDef(i)) {
const 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.
if (isDef(vnode.componentInstance)) {
initComponent(vnode, insertedVnodeQueue)
if (isReactivated) {
reactivateComponent(vnode, insertedVnodeQueue, parentElm, refElm)
}
return true
}
}
}
function initComponent (vnode, insertedVnodeQueue) {
if (vnode.data.pendingInsert) {
insertedVnodeQueue.push.apply(insertedVnodeQueue, vnode.data.pendingInsert)
}
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) {
let 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.
let 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) {
if (parent) {
if (ref) {
nodeOps.insertBefore(parent, elm, ref)
} else {
nodeOps.appendChild(parent, elm)
}
}
}
function createChildren (vnode, children, insertedVnodeQueue) {
if (Array.isArray(children)) {
for (let i = 0; i < children.length; ++i) {
createElm(children[i], insertedVnodeQueue, vnode.elm, null, true)
}
} else if (isPrimitive(vnode.text)) {
nodeOps.appendChild(vnode.elm, nodeOps.createTextNode(vnode.text))
}
}
function isPatchable (vnode) {
while (vnode.componentInstance) {
vnode = vnode.componentInstance._vnode
}
return isDef(vnode.tag)
}
function invokeCreateHooks (vnode, insertedVnodeQueue) {
for (let i = 0; i < cbs.create.length; ++i) {
cbs.create[i](emptyNode, vnode)
}
i = vnode.data.hook // Reuse variable
if (isDef(i)) {
if (i.create) i.create(emptyNode, vnode)
if (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) {
let i
if (isDef(i = vnode.context) && isDef(i = i.$options._scopeId)) {
nodeOps.setAttribute(vnode.elm, i, '')
}
if (isDef(i = activeInstance) &&
i !== vnode.context &&
isDef(i = i.$options._scopeId)) {
nodeOps.setAttribute(vnode.elm, i, '')
}
}
function addVnodes (parentElm, refElm, vnodes, startIdx, endIdx, insertedVnodeQueue) {
for (; startIdx <= endIdx; ++startIdx) {
createElm(vnodes[startIdx], insertedVnodeQueue, parentElm, refElm)
}
}
function invokeDestroyHook (vnode) {
let i, j
const 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) {
const 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 (rm || isDef(vnode.data)) {
const listeners = cbs.remove.length + 1
if (!rm) {
// directly removing
rm = createRmCb(vnode.elm, listeners)
} else {
// we have a recursively passed down rm callback
// increase the listeners count
rm.listeners += 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) {
let oldStartIdx = 0
let newStartIdx = 0
let oldEndIdx = oldCh.length - 1
let oldStartVnode = oldCh[0]
let oldEndVnode = oldCh[oldEndIdx]
let newEndIdx = newCh.length - 1
let newStartVnode = newCh[0]
let newEndVnode = newCh[newEndIdx]
let oldKeyToIdx, idxInOld, elmToMove, refElm
// removeOnly is a special flag used only by <transition-group>
// to ensure removed elements stay in correct relative positions
// during leaving transitions
const canMove = !removeOnly
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] : null
if (isUndef(idxInOld)) { // New element
createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm)
newStartVnode = newCh[++newStartIdx]
} else {
elmToMove = oldCh[idxInOld]
/* istanbul ignore if */
if (process.env.NODE_ENV !== 'production' && !elmToMove) {
warn(
'It seems there are duplicate keys that is causing an update error. ' +
'Make sure each v-for item has a unique key.'
)
}
if (sameVnode(elmToMove, newStartVnode)) {
patchVnode(elmToMove, newStartVnode, insertedVnodeQueue)
oldCh[idxInOld] = undefined
canMove && nodeOps.insertBefore(parentElm, newStartVnode.elm, oldStartVnode.elm)
newStartVnode = newCh[++newStartIdx]
} else {
// same key but different element. treat as new element
createElm(newStartVnode, insertedVnodeQueue, parentElm, oldStartVnode.elm)
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)
}
}
function patchVnode (oldVnode, vnode, insertedVnodeQueue, removeOnly) {
if (oldVnode === vnode) {
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 (vnode.isStatic &&
oldVnode.isStatic &&
vnode.key === oldVnode.key &&
(vnode.isCloned || vnode.isOnce)) {
vnode.elm = oldVnode.elm
vnode.componentInstance = oldVnode.componentInstance
return
}
let i
const data = vnode.data
const hasData = isDef(data)
if (hasData && isDef(i = data.hook) && isDef(i = i.prepatch)) {
i(oldVnode, vnode)
}
const elm = vnode.elm = oldVnode.elm
const oldCh = oldVnode.children
const ch = vnode.children
if (hasData && 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 (hasData) {
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 (initial && vnode.parent) {
vnode.parent.data.pendingInsert = queue
} else {
for (let i = 0; i < queue.length; ++i) {
queue[i].data.hook.insert(queue[i])
}
}
}
let bailed = 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
const isRenderedModule = makeMap('attrs,style,class,staticClass,staticStyle,key')
// Note: this is a browser-only function so we can assume elms are DOM nodes.
function hydrate (elm, vnode, insertedVnodeQueue) {
if (process.env.NODE_ENV !== 'production') {
if (!assertNodeMatch(elm, vnode)) {
return false
}
}
vnode.elm = elm
const { tag, data, children } = vnode
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 {
let childrenMatch = true
let childNode = elm.firstChild
for (let i = 0; i < children.length; i++) {
if (!childNode || !hydrate(childNode, children[i], insertedVnodeQueue)) {
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) {
if (process.env.NODE_ENV !== 'production' &&
typeof console !== 'undefined' &&
!bailed) {
bailed = true
console.warn('Parent: ', elm)
console.warn('Mismatching childNodes vs. VNodes: ', elm.childNodes, children)
}
return false
}
}
}
if (isDef(data)) {
for (const key in data) {
if (!isRenderedModule(key)) {
invokeCreateHooks(vnode, insertedVnodeQueue)
break
}
}
}
} else if (elm.data !== vnode.text) {
elm.data = vnode.text
}
return true
}
function assertNodeMatch (node, vnode) {
if (vnode.tag) {
return (
vnode.tag.indexOf('vue-component') === 0 ||
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 (!vnode) {
if (oldVnode) invokeDestroyHook(oldVnode)
return
}
let isInitialPatch = false
const insertedVnodeQueue = []
if (!oldVnode) {
// empty mount (likely as component), create new root element
isInitialPatch = true
createElm(vnode, insertedVnodeQueue, parentElm, refElm)
} else {
const 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('server-rendered')) {
oldVnode.removeAttribute('server-rendered')
hydrating = true
}
if (hydrating) {
if (hydrate(oldVnode, vnode, insertedVnodeQueue)) {
invokeInsertHook(vnode, insertedVnodeQueue, true)
return oldVnode
} else if (process.env.NODE_ENV !== 'production') {
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
const oldElm = oldVnode.elm
const parentElm = nodeOps.parentNode(oldElm)
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,
nodeOps.nextSibling(oldElm)
)
if (vnode.parent) {
// component root element replaced.
// update parent placeholder node element, recursively
let ancestor = vnode.parent
while (ancestor) {
ancestor.elm = vnode.elm
ancestor = ancestor.parent
}
if (isPatchable(vnode)) {
for (let i = 0; i < cbs.create.length; ++i) {
cbs.create[i](emptyNode, vnode.parent)
}
}
}
if (parentElm !== null) {
removeVnodes(parentElm, [oldVnode], 0, 0)
} else if (isDef(oldVnode.tag)) {
invokeDestroyHook(oldVnode)
}
}
}
invokeInsertHook(vnode, insertedVnodeQueue, isInitialPatch)
return vnode.elm
}
}