refactor(types): use stricter settings

fix #847

packages/runtime-core/src/apiCreateApp.ts

@@ -12,6 +12,7 @@ import { InjectionKey } from './apiInject'
 import { isFunction, NO, isObject } from '@vue/shared'
 import { warn } from './warning'
 import { createVNode, cloneVNode, VNode } from './vnode'
+import { RootHydrateFunction } from './hydration'
 
 export interface App<HostElement = any> {
   config: AppConfig
@@ -91,11 +92,11 @@ export type CreateAppFunction<HostElement> = (
   rootProps?: Data | null
 ) => App<HostElement>
 
-export function createAppAPI<HostNode, HostElement>(
-  render: RootRenderFunction<HostNode, HostElement>,
-  hydrate?: (vnode: VNode, container: Element) => void
+export function createAppAPI<HostElement>(
+  render: RootRenderFunction,
+  hydrate?: RootHydrateFunction
 ): CreateAppFunction<HostElement> {
-  return function createApp(rootComponent: Component, rootProps = null) {
+  return function createApp(rootComponent, rootProps = null) {
     if (rootProps != null && !isObject(rootProps)) {
       __DEV__ && warn(`root props passed to app.mount() must be an object.`)
       rootProps = null
@@ -107,7 +108,7 @@ export function createAppAPI<HostNode, HostElement>(
     let isMounted = false
 
     const app: App = {
-      _component: rootComponent,
+      _component: rootComponent as Component,
       _props: rootProps,
       _container: null,
       _context: context,
@@ -189,7 +190,7 @@ export function createAppAPI<HostNode, HostElement>(
 
       mount(rootContainer: HostElement, isHydrate?: boolean): any {
         if (!isMounted) {
-          const vnode = createVNode(rootComponent, rootProps)
+          const vnode = createVNode(rootComponent as Component, rootProps)
           // store app context on the root VNode.
           // this will be set on the root instance on initial mount.
           vnode.appContext = context
@@ -202,7 +203,7 @@ export function createAppAPI<HostNode, HostElement>(
           }
 
           if (isHydrate && hydrate) {
-            hydrate(vnode, rootContainer as any)
+            hydrate(vnode as VNode<Node, Element>, rootContainer as any)
           } else {
             render(vnode, rootContainer)
           }