feat(types): feat(types): add ComponentCustomProperties interface (#982)

packages/runtime-core/src/apiWatch.ts

@@ -20,7 +20,6 @@ import {
 import {
   currentInstance,
   ComponentInternalInstance,
-  Data,
   isInSSRComponentSetup,
   recordInstanceBoundEffect
 } from './component'
@@ -276,9 +275,11 @@ export function instanceWatch(
   cb: Function,
   options?: WatchOptions
 ): StopHandle {
-  const ctx = this.proxy as Data
-  const getter = isString(source) ? () => ctx[source] : source.bind(ctx)
-  const stop = watch(getter, cb.bind(ctx), options)
+  const publicThis = this.proxy as any
+  const getter = isString(source)
+    ? () => publicThis[source]
+    : source.bind(publicThis)
+  const stop = watch(getter, cb.bind(publicThis), options)
   onBeforeUnmount(stop, this)
   return stop
 }