官方实现

2024年03月15日

柏拉文

越努力，越幸运

一、packages/runtime-dom/src/index.ts createApp()

---

export const createApp = ((...args) => {
  const app = ensureRenderer().createApp(...args)

  if (__DEV__) {
    injectNativeTagCheck(app)
    injectCompilerOptionsCheck(app)
  }

  const { mount } = app
  app.mount = (containerOrSelector: Element | ShadowRoot | string): any => {
    const container = normalizeContainer(containerOrSelector)
    if (!container) return

    const component = app._component
    if (!isFunction(component) && !component.render && !component.template) {
      // __UNSAFE__
      // Reason: potential execution of JS expressions in in-DOM template.
      // The user must make sure the in-DOM template is trusted. If it's
      // rendered by the server, the template should not contain any user data.
      component.template = container.innerHTML
      // 2.x compat check
      if (__COMPAT__ && __DEV__) {
        for (let i = 0; i < container.attributes.length; i++) {
          const attr = container.attributes[i]
          if (attr.name !== 'v-cloak' && /^(v-|:|@)/.test(attr.name)) {
            compatUtils.warnDeprecation(
              DeprecationTypes.GLOBAL_MOUNT_CONTAINER,
              null
            )
            break
          }
        }
      }
    }

    // clear content before mounting
    container.innerHTML = ''
    const proxy = mount(container, false, container instanceof SVGElement)
    if (container instanceof Element) {
      container.removeAttribute('v-cloak')
      container.setAttribute('data-v-app', '')
    }
    return proxy
  }

  return app
}) as CreateAppFunction<Element>

二、packages/runtime-dom/src/index.ts ensureRenderer()

---

function ensureRenderer() {
  return (
    renderer ||
    (renderer = createRenderer<Node, Element | ShadowRoot>(rendererOptions))
  )
}

三、packages/runtime-core/src/renderer.ts createRenderer()

---

export function createRenderer<
  HostNode = RendererNode,
  HostElement = RendererElement
>(options: RendererOptions<HostNode, HostElement>) {
  return baseCreateRenderer<HostNode, HostElement>(options)
}

四、packages/runtime-core/src/renderer.ts baseCreateRenderer()

---

function baseCreateRenderer(
  options: RendererOptions,
  createHydrationFns?: typeof createHydrationFunctions
): any {
  // compile-time feature flags check
  if (__ESM_BUNDLER__ && !__TEST__) {
    initFeatureFlags()
  }

  const target = getGlobalThis()
  target.__VUE__ = true
  if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) {
    setDevtoolsHook(target.__VUE_DEVTOOLS_GLOBAL_HOOK__, target)
  }

  const {
    insert: hostInsert,
    remove: hostRemove,
    patchProp: hostPatchProp,
    createElement: hostCreateElement,
    createText: hostCreateText,
    createComment: hostCreateComment,
    setText: hostSetText,
    setElementText: hostSetElementText,
    parentNode: hostParentNode,
    nextSibling: hostNextSibling,
    setScopeId: hostSetScopeId = NOOP,
    insertStaticContent: hostInsertStaticContent
  } = options

  // Note: functions inside this closure should use `const xxx = () => {}`
  // style in order to prevent being inlined by minifiers.
  const patch: PatchFn = (
  ) => {
  }

  const processText: ProcessTextOrCommentFn = (n1, n2, container, anchor) => {
  }

  const processCommentNode: ProcessTextOrCommentFn = (
  ) => {
  }

  const mountStaticNode = (
  ) => {
  }

  /**
   * Dev / HMR only
   */
  const patchStaticNode = (
  ) => {
  }

  const moveStaticNode = (
  ) => {
  }

  const processElement = (
  ) => {
  }

  const mountElement = (
  ) => {
  }

  const setScopeId = (
  ) => {
  }

  const mountChildren: MountChildrenFn = (
  ) => {
  }

  const patchElement = (
  ) => {
  }

  // The fast path for blocks.
  const patchBlockChildren: PatchBlockChildrenFn = (
  ) => {
  }

  const processFragment = (
  ) => {
  }

  const processComponent = (
  ) => {
  }

  const mountComponent: MountComponentFn = (
  ) => {
  }

  const updateComponent = (n1: VNode, n2: VNode, optimized: boolean) => {
  }

  const setupRenderEffect: SetupRenderEffectFn = (
  ) => {
  }

  const updateComponentPreRender = (
  ) => {
  }

  const patchChildren: PatchChildrenFn = (
  ) => {
  }

  const patchUnkeyedChildren = (
  ) => {
  }

  // can be all-keyed or mixed
  const patchKeyedChildren = (
  ) => {
  }

  const move: MoveFn = (
  ) => {
  }

  const unmount: UnmountFn = (
  ) => {
  }

  const remove: RemoveFn = vnode => {
  }

  const removeFragment = (cur: RendererNode, end: RendererNode) => {
  }

  const unmountComponent = (
  ) => {
  }

  const unmountChildren: UnmountChildrenFn = (
    
  ) => {
  }

  const getNextHostNode: NextFn = vnode => {}

  const render: RootRenderFunction = (vnode, container, isSVG) => {
    if (vnode == null) {
      if (container._vnode) {
        unmount(container._vnode, null, null, true)
      }
    } else {
      patch(container._vnode || null, vnode, container, null, null, null, isSVG)
    }
    flushPreFlushCbs()
    flushPostFlushCbs()
    container._vnode = vnode
  }

  return {
    render,
    hydrate,
    createApp: createAppAPI(render, hydrate)
  }
}

五、packages/runtime-core/src/apiCreateApp.ts createAppAPI()

---

export function createAppAPI<HostElement>(
  render: RootRenderFunction<HostElement>,
  hydrate?: RootHydrateFunction
): CreateAppFunction<HostElement> {
  return function createApp(rootComponent, rootProps = null) {
    if (!isFunction(rootComponent)) {
      rootComponent = extend({}, rootComponent)
    }

    if (rootProps != null && !isObject(rootProps)) {
      __DEV__ && warn(`root props passed to app.mount() must be an object.`)
      rootProps = null
    }

    const context = createAppContext()

    // TODO remove in 3.4
    if (__DEV__) {
      Object.defineProperty(context.config, 'unwrapInjectedRef', {
        get() {
          return true
        },
        set() {
          warn(
            `app.config.unwrapInjectedRef has been deprecated. ` +
              `3.3 now always unwraps injected refs in Options API.`
          )
        }
      })
    }

    const installedPlugins = new Set()

    let isMounted = false

    const app: App = (context.app = {
      _uid: uid++,
      _component: rootComponent as ConcreteComponent,
      _props: rootProps,
      _container: null,
      _context: context,
      _instance: null,

      version,

      get config() {
        return context.config
      },

      set config(v) {
        if (__DEV__) {
          warn(
            `app.config cannot be replaced. Modify individual options instead.`
          )
        }
      },

      use(plugin: Plugin, ...options: any[]) {
        if (installedPlugins.has(plugin)) {
          __DEV__ && warn(`Plugin has already been applied to target app.`)
        } else if (plugin && isFunction(plugin.install)) {
          installedPlugins.add(plugin)
          plugin.install(app, ...options)
        } else if (isFunction(plugin)) {
          installedPlugins.add(plugin)
          plugin(app, ...options)
        } else if (__DEV__) {
          warn(
            `A plugin must either be a function or an object with an "install" ` +
              `function.`
          )
        }
        return app
      },

      mixin(mixin: ComponentOptions) {
        if (__FEATURE_OPTIONS_API__) {
          if (!context.mixins.includes(mixin)) {
            context.mixins.push(mixin)
          } else if (__DEV__) {
            warn(
              'Mixin has already been applied to target app' +
                (mixin.name ? `: ${mixin.name}` : '')
            )
          }
        } else if (__DEV__) {
          warn('Mixins are only available in builds supporting Options API')
        }
        return app
      },

      component(name: string, component?: Component): any {
        if (__DEV__) {
          validateComponentName(name, context.config)
        }
        if (!component) {
          return context.components[name]
        }
        if (__DEV__ && context.components[name]) {
          warn(`Component "${name}" has already been registered in target app.`)
        }
        context.components[name] = component
        return app
      },

      directive(name: string, directive?: Directive) {
        if (__DEV__) {
          validateDirectiveName(name)
        }

        if (!directive) {
          return context.directives[name] as any
        }
        if (__DEV__ && context.directives[name]) {
          warn(`Directive "${name}" has already been registered in target app.`)
        }
        context.directives[name] = directive
        return app
      },

      mount(
        rootContainer: HostElement,
        isHydrate?: boolean,
        isSVG?: boolean
      ): any {
        if (!isMounted) {
          // #5571
          if (__DEV__ && (rootContainer as any).__vue_app__) {
            warn(
              `There is already an app instance mounted on the host container.\n` +
                ` If you want to mount another app on the same host container,` +
                ` you need to unmount the previous app by calling \`app.unmount()\` first.`
            )
          }
          const vnode = createVNode(rootComponent, rootProps)
          // store app context on the root VNode.
          // this will be set on the root instance on initial mount.
          vnode.appContext = context

          // HMR root reload
          if (__DEV__) {
            context.reload = () => {
              render(cloneVNode(vnode), rootContainer, isSVG)
            }
          }

          if (isHydrate && hydrate) {
            hydrate(vnode as VNode<Node, Element>, rootContainer as any)
          } else {
            render(vnode, rootContainer, isSVG)
          }
          isMounted = true
          app._container = rootContainer
          // for devtools and telemetry
          ;(rootContainer as any).__vue_app__ = app

          if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) {
            app._instance = vnode.component
            devtoolsInitApp(app, version)
          }

          return getExposeProxy(vnode.component!) || vnode.component!.proxy
        } else if (__DEV__) {
          warn(
            `App has already been mounted.\n` +
              `If you want to remount the same app, move your app creation logic ` +
              `into a factory function and create fresh app instances for each ` +
              `mount - e.g. \`const createMyApp = () => createApp(App)\``
          )
        }
      },

      unmount() {
        if (isMounted) {
          render(null, app._container)
          if (__DEV__ || __FEATURE_PROD_DEVTOOLS__) {
            app._instance = null
            devtoolsUnmountApp(app)
          }
          delete app._container.__vue_app__
        } else if (__DEV__) {
          warn(`Cannot unmount an app that is not mounted.`)
        }
      },

      provide(key, value) {
        if (__DEV__ && (key as string | symbol) in context.provides) {
          warn(
            `App already provides property with key "${String(key)}". ` +
              `It will be overwritten with the new value.`
          )
        }

        context.provides[key as string | symbol] = value

        return app
      },

      runWithContext(fn) {
        currentApp = app
        try {
          return fn()
        } finally {
          currentApp = null
        }
      }
    })

    if (__COMPAT__) {
      installAppCompatProperties(app, context, render)
    }

    return app
  }
}