# 首次加载(渲染-组件)
前言
render会区分不同种类的组件，会转化为不同种类的vnode
# 1.component
- /src/vue/src/core/vdom/create-component.ts
export function createComponent(
Ctor: typeof Component | Function | ComponentOptions | void,
data: VNodeData | undefined,
context: Component,
children?: Array<VNode>,
tag?: string
): VNode | Array<VNode> | void {
if (isUndef(Ctor)) {
return
}
const baseCtor = context.$options._base
// plain options object: turn it into a constructor
if (isObject(Ctor)) {
Ctor = baseCtor.extend(Ctor as typeof Component)
}
// if at this stage it's not a constructor or an async component factory,
// reject.
if (typeof Ctor !== 'function') {
if (__DEV__) {
warn(`Invalid Component definition: ${String(Ctor)}`, context)
}
return
}
// async component
let asyncFactory
// @ts-expect-error
if (isUndef(Ctor.cid)) {
asyncFactory = Ctor
Ctor = resolveAsyncComponent(asyncFactory, baseCtor)
if (Ctor === undefined) {
// return a placeholder node for async component, which is rendered
// as a comment node but preserves all the raw information for the node.
// the information will be used for async server-rendering and hydration.
return createAsyncPlaceholder(asyncFactory, data, context, children, tag)
}
}
data = data || {}
// resolve constructor options in case global mixins are applied after
// component constructor creation
resolveConstructorOptions(Ctor as typeof Component)
// transform component v-model data into props & events
if (isDef(data.model)) {
// @ts-expect-error
transformModel(Ctor.options, data)
}
// extract props
// @ts-expect-error
const propsData = extractPropsFromVNodeData(data, Ctor, tag)
// functional component
// @ts-expect-error
if (isTrue(Ctor.options.functional)) {
return createFunctionalComponent(
Ctor as typeof Component,
propsData,
data,
context,
children
)
}
// extract listeners, since these needs to be treated as
// child component listeners instead of DOM listeners
const listeners = data.on
// replace with listeners with .native modifier
// so it gets processed during parent component patch.
data.on = data.nativeOn
// @ts-expect-error
if (isTrue(Ctor.options.abstract)) {
// abstract components do not keep anything
// other than props & listeners & slot
// work around flow
const slot = data.slot
data = {}
if (slot) {
data.slot = slot
}
}
// install component management hooks onto the placeholder node
installComponentHooks(data)
// return a placeholder vnode
// @ts-expect-error
const name = getComponentName(Ctor.options) || tag
const vnode = new VNode(
// @ts-expect-error
`vue-component-${Ctor.cid}${name ? `-${name}` : ''}`,
data,
undefined,
undefined,
undefined,
context,
// @ts-expect-error
{ Ctor, propsData, listeners, tag, children },
asyncFactory
)
return vnode
}1
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# 1.同步组件
# 1.1 extend
# 1.2 installComponentHooks
- /src/vue/src/core/vdom/create-component.ts
function installComponentHooks(data: VNodeData) {
const hooks = data.hook || (data.hook = {})
for (let i = 0; i < hooksToMerge.length; i++) {
const key = hooksToMerge[i]
const existing = hooks[key]
const toMerge = componentVNodeHooks[key]
// @ts-expect-error
if (existing !== toMerge && !(existing && existing._merged)) {
hooks[key] = existing ? mergeHook(toMerge, existing) : toMerge
}
}
}1
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- /src/vue/src/core/vdom/create-component.ts
const componentVNodeHooks = {
init(vnode: VNodeWithData, hydrating: boolean): boolean | void {
if (
vnode.componentInstance &&
!vnode.componentInstance._isDestroyed &&
vnode.data.keepAlive
) {
// kept-alive components, treat as a patch
const mountedNode: any = vnode // work around flow
componentVNodeHooks.prepatch(mountedNode, mountedNode)
} else {
const child = (vnode.componentInstance = createComponentInstanceForVnode(
vnode,
activeInstance
))
child.$mount(hydrating ? vnode.elm : undefined, hydrating)
}
},
prepatch(oldVnode: MountedComponentVNode, vnode: MountedComponentVNode) {
const options = vnode.componentOptions
const child = (vnode.componentInstance = oldVnode.componentInstance)
updateChildComponent(
child,
options.propsData, // updated props
options.listeners, // updated listeners
vnode, // new parent vnode
options.children // new children
)
},
insert(vnode: MountedComponentVNode) {
const { context, componentInstance } = vnode
if (!componentInstance._isMounted) {
componentInstance._isMounted = true
callHook(componentInstance, 'mounted')
}
if (vnode.data.keepAlive) {
if (context._isMounted) {
// vue-router#1212
// During updates, a kept-alive component's child components may
// change, so directly walking the tree here may call activated hooks
// on incorrect children. Instead we push them into a queue which will
// be processed after the whole patch process ended.
queueActivatedComponent(componentInstance)
} else {
activateChildComponent(componentInstance, true /* direct */)
}
}
},
destroy(vnode: MountedComponentVNode) {
const { componentInstance } = vnode
if (!componentInstance._isDestroyed) {
if (!vnode.data.keepAlive) {
componentInstance.$destroy()
} else {
deactivateChildComponent(componentInstance, true /* direct */)
}
}
}
}1
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# 2.异步组件
# 2.1 resolveAsyncComponent
- /src/vue/src/core/vdom/helpers/resolve-async-component.ts
export function resolveAsyncComponent(
factory: { (...args: any[]): any; [keye: string]: any },
baseCtor: typeof Component
): typeof Component | void {
if (isTrue(factory.error) && isDef(factory.errorComp)) {
return factory.errorComp
}
if (isDef(factory.resolved)) {
return factory.resolved
}
const owner = currentRenderingInstance
if (owner && isDef(factory.owners) && factory.owners.indexOf(owner) === -1) {
// already pending
factory.owners.push(owner)
}
if (isTrue(factory.loading) && isDef(factory.loadingComp)) {
return factory.loadingComp
}
if (owner && !isDef(factory.owners)) {
const owners = (factory.owners = [owner])
let sync = true
let timerLoading: number | null = null
let timerTimeout: number | null = null
owner.$on('hook:destroyed', () => remove(owners, owner))
const forceRender = (renderCompleted: boolean) => {
for (let i = 0, l = owners.length; i < l; i++) {
owners[i].$forceUpdate()
}
if (renderCompleted) {
owners.length = 0
if (timerLoading !== null) {
clearTimeout(timerLoading)
timerLoading = null
}
if (timerTimeout !== null) {
clearTimeout(timerTimeout)
timerTimeout = null
}
}
}
const resolve = once((res: Object | Component) => {
// cache resolved
factory.resolved = ensureCtor(res, baseCtor)
// invoke callbacks only if this is not a synchronous resolve
// (async resolves are shimmed as synchronous during SSR)
if (!sync) {
forceRender(true)
} else {
owners.length = 0
}
})
const reject = once(reason => {
__DEV__ &&
warn(
`Failed to resolve async component: ${String(factory)}` +
(reason ? `\nReason: ${reason}` : '')
)
if (isDef(factory.errorComp)) {
factory.error = true
forceRender(true)
}
})
const res = factory(resolve, reject)
if (isObject(res)) {
if (isPromise(res)) {
// () => Promise
if (isUndef(factory.resolved)) {
res.then(resolve, reject)
}
} else if (isPromise(res.component)) {
res.component.then(resolve, reject)
if (isDef(res.error)) {
factory.errorComp = ensureCtor(res.error, baseCtor)
}
if (isDef(res.loading)) {
factory.loadingComp = ensureCtor(res.loading, baseCtor)
if (res.delay === 0) {
factory.loading = true
} else {
// @ts-expect-error NodeJS timeout type
timerLoading = setTimeout(() => {
timerLoading = null
if (isUndef(factory.resolved) && isUndef(factory.error)) {
factory.loading = true
forceRender(false)
}
}, res.delay || 200)
}
}
if (isDef(res.timeout)) {
// @ts-expect-error NodeJS timeout type
timerTimeout = setTimeout(() => {
timerTimeout = null
if (isUndef(factory.resolved)) {
reject(__DEV__ ? `timeout (${res.timeout}ms)` : null)
}
}, res.timeout)
}
}
}
sync = false
// return in case resolved synchronously
return factory.loading ? factory.loadingComp : factory.resolved
}
}1
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# 2.2 createAsyncPlaceholder
- /src/vue/src/core/vdom/helpers/resolve-async-component.ts
export function createAsyncPlaceholder(
factory: Function,
data: VNodeData | undefined,
context: Component,
children: Array<VNode> | undefined,
tag?: string
): VNode {
const node = createEmptyVNode()
node.asyncFactory = factory
node.asyncMeta = { data, context, children, tag }
return node
}1
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# 3.函数式组件
- /src/vue/src/core/vdom/create-functional-component.ts
export function createFunctionalComponent(
Ctor: typeof Component,
propsData: Object | undefined,
data: VNodeData,
contextVm: Component,
children?: Array<VNode>
): VNode | Array<VNode> | void {
const options = Ctor.options
const props = {}
const propOptions = options.props
if (isDef(propOptions)) {
for (const key in propOptions) {
props[key] = validateProp(key, propOptions, propsData || emptyObject)
}
} else {
if (isDef(data.attrs)) mergeProps(props, data.attrs)
if (isDef(data.props)) mergeProps(props, data.props)
}
const renderContext = new FunctionalRenderContext(
data,
props,
children,
contextVm,
Ctor
)
const vnode = options.render.call(null, renderContext._c, renderContext)
if (vnode instanceof VNode) {
return cloneAndMarkFunctionalResult(
vnode,
data,
renderContext.parent,
options,
renderContext
)
} else if (isArray(vnode)) {
const vnodes = normalizeChildren(vnode) || []
const res = new Array(vnodes.length)
for (let i = 0; i < vnodes.length; i++) {
res[i] = cloneAndMarkFunctionalResult(
vnodes[i],
data,
renderContext.parent,
options,
renderContext
)
}
return res
}
}1
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