fix: types

Author: sxzz

packages/dts-test/defineComponent.test-d.tsx

@@ -1415,8 +1415,8 @@ describe('slots', () => {
       item: [number]
     }>,
     setup(props, { slots }) {
-      expectType<(foo: string, bar: number) => any>(slots.default)
-      expectType<(scope: number) => any>(slots.item)
+      expectType<undefined | ((foo: string, bar: number) => any)>(slots.default)
+      expectType<undefined | ((scope: number) => any)>(slots.item)
     }
   })
 

packages/dts-test/functionalComponent.test-d.tsx

@@ -1,4 +1,4 @@
-import { h, Text, FunctionalComponent, Component, SlotsType, VNode } from 'vue'
+import { h, Text, FunctionalComponent, Component, VNode } from 'vue'
 import { expectType } from './utils'
 
 // simple function signature
@@ -73,7 +73,7 @@ const Quux: FunctionalComponent<{}, {}, { default: [foo: number] }> = (
   props,
   { emit, slots }
 ) => {
-  expectType<{ default: (foo: number) => VNode[] }>(slots)
+  expectType<{ default: undefined | ((foo: number) => VNode[]) }>(slots)
 }
 expectType<Component>(Quux)
 ;<Quux />

packages/runtime-core/src/component.ts

@@ -125,7 +125,7 @@ export interface ComponentInternalOptions {
 export interface FunctionalComponent<
   P = {},
   E extends EmitsOptions = {},
-  S extends Record<string, any[]> = {}
+  S extends Record<string, any[]> = Record<string, any[]>
 > extends ComponentInternalOptions {
   // use of any here is intentional so it can be a valid JSX Element constructor
   (props: P, ctx: Omit<SetupContext<E, SlotsType<S>>, 'expose'>): any

packages/runtime-core/src/componentSlots.ts

@@ -41,9 +41,9 @@ export type TypedSlots<S extends SlotsType> = [keyof S] extends [never]
   ? Slots
   : Readonly<
       Prettify<{
-        [K in keyof NonNullable<S[typeof SlotSymbol]>]: Slot<
-          NonNullable<S[typeof SlotSymbol]>[K]
-        >
+        [K in keyof NonNullable<S[typeof SlotSymbol]>]:
+          | Slot<NonNullable<S[typeof SlotSymbol]>[K]>
+          | undefined
       }>
     >