types: improve computed types (#343)

packages/runtime-core/src/apiOptions.ts

@@ -30,7 +30,11 @@ import {
   DebuggerHook,
   ErrorCapturedHook
 } from './apiLifecycle'
-import { reactive } from '@vue/reactivity'
+import {
+  reactive,
+  ComputedGetter,
+  WritableComputedOptions
+} from '@vue/reactivity'
 import { ComponentObjectPropsOptions, ExtractPropTypes } from './componentProps'
 import { Directive } from './directives'
 import { ComponentPublicInstance } from './componentProxy'
@@ -100,14 +104,10 @@ export type ComponentOptions =
 // TODO legacy component definition also supports constructors with .options
 type LegacyComponent = ComponentOptions
 
-export interface ComputedOptions {
-  [key: string]:
-    | Function
-    | {
-        get: Function
-        set: Function
-      }
-}
+export type ComputedOptions = Record<
+  string,
+  ComputedGetter<any> | WritableComputedOptions<any>
+>
 
 export interface MethodOptions {
   [key: string]: Function