Vue2.x学习笔记

# 销毁操作(销毁-组件)

前言

这里主要介绍没有老vnode，只有新vnode的情况，次中情况下就是创建组件实例，组件实例中会添加组件相关的生命周期

# 1.组件钩子

  • /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 */)
      }
    }
  }
}
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组件的不同生命周期：

  • 有keep-alive：通过deactivateChildComponent进行销毁
  • 无keep-alive：组件通过$destroy进行销毁

# 2 deactivateChildComponent

# 3.$destroy

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