From 5179d328d950015e7fb2a74fe1a8518fd8d2c94e Mon Sep 17 00:00:00 2001
From: Tycho <jh.leong@outlook.com>
Date: Thu, 22 May 2025 08:03:33 +0800
Subject: [PATCH] fix(types): exclude `undefined` from inferred prop types with
 default values (#13007)

close #13006
---
 .../dts-test/defineComponent.test-d.tsx       | 29 +++++++++++++++++++
 packages/runtime-core/src/componentProps.ts   |  4 ++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index fda3ca485..1967668dc 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -20,6 +20,9 @@ import { type IsAny, type IsUnion, describe, expectType } from './utils'
 describe('with object props', () => {
   interface ExpectedProps {
     a?: number | undefined
+    aa: number
+    aaa: number | null
+    aaaa: number | undefined
     b: string
     e?: Function
     h: boolean
@@ -53,6 +56,19 @@ describe('with object props', () => {
 
   const props = {
     a: Number,
+    aa: {
+      type: Number as PropType<number | undefined>,
+      default: 1,
+    },
+    aaa: {
+      type: Number as PropType<number | null>,
+      default: 1,
+    },
+    aaaa: {
+      type: Number as PropType<number | undefined>,
+      // `as const` prevents widening to `boolean` (keeps literal `true` type)
+      required: true as const,
+    },
     // required should make property non-void
     b: {
       type: String,
@@ -146,6 +162,13 @@ describe('with object props', () => {
     setup(props) {
       // type assertion. See https://github.com/SamVerschueren/tsd
       expectType<ExpectedProps['a']>(props.a)
+      expectType<ExpectedProps['aa']>(props.aa)
+      expectType<ExpectedProps['aaa']>(props.aaa)
+
+      // @ts-expect-error should included `undefined`
+      expectType<number>(props.aaaa)
+      expectType<ExpectedProps['aaaa']>(props.aaaa)
+
       expectType<ExpectedProps['b']>(props.b)
       expectType<ExpectedProps['e']>(props.e)
       expectType<ExpectedProps['h']>(props.h)
@@ -198,6 +221,8 @@ describe('with object props', () => {
     render() {
       const props = this.$props
       expectType<ExpectedProps['a']>(props.a)
+      expectType<ExpectedProps['aa']>(props.aa)
+      expectType<ExpectedProps['aaa']>(props.aaa)
       expectType<ExpectedProps['b']>(props.b)
       expectType<ExpectedProps['e']>(props.e)
       expectType<ExpectedProps['h']>(props.h)
@@ -225,6 +250,8 @@ describe('with object props', () => {
 
       // should also expose declared props on `this`
       expectType<ExpectedProps['a']>(this.a)
+      expectType<ExpectedProps['aa']>(this.aa)
+      expectType<ExpectedProps['aaa']>(this.aaa)
       expectType<ExpectedProps['b']>(this.b)
       expectType<ExpectedProps['e']>(this.e)
       expectType<ExpectedProps['h']>(this.h)
@@ -269,6 +296,7 @@ describe('with object props', () => {
   expectType<JSX.Element>(
     <MyComponent
       a={1}
+      aaaa={1}
       b="b"
       bb="bb"
       e={() => {}}
@@ -295,6 +323,7 @@ describe('with object props', () => {
 
   expectType<Component>(
     <MyComponent
+      aaaa={1}
       b="b"
       dd={{ n: 1 }}
       ddd={['ddd']}
diff --git a/packages/runtime-core/src/componentProps.ts b/packages/runtime-core/src/componentProps.ts
index 8baa78086..775eb8b67 100644
--- a/packages/runtime-core/src/componentProps.ts
+++ b/packages/runtime-core/src/componentProps.ts
@@ -143,7 +143,9 @@ type InferPropType<T, NullAsAny = true> = [T] extends [null]
 export type ExtractPropTypes<O> = {
   // use `keyof Pick<O, RequiredKeys<O>>` instead of `RequiredKeys<O>` to
   // support IDE features
-  [K in keyof Pick<O, RequiredKeys<O>>]: InferPropType<O[K]>
+  [K in keyof Pick<O, RequiredKeys<O>>]: O[K] extends { default: any }
+    ? Exclude<InferPropType<O[K]>, undefined>
+    : InferPropType<O[K]>
 } & {
   // use `keyof Pick<O, OptionalKeys<O>>` instead of `OptionalKeys<O>` to
   // support IDE features