chore: improve code according to review advice

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

@@ -1299,7 +1299,7 @@ describe('define attrs', () => {
     expectType<JSX.Element>(<MyComp />)
   })
 
-  test('define attrs w/ no attrs', () => {
+  test('define no attrs w/ object props', () => {
     const MyComp = defineComponent({
       props: {
         foo: String
@@ -1312,6 +1312,19 @@ describe('define attrs', () => {
     expectType<JSX.Element>(<MyComp foo="1" bar={1} />)
   })
 
+  test('define no attrs w/ functional component', () => {
+    const MyComp = defineComponent((props: { foo: string }, ctx) => {
+      expectType<unknown>(ctx.attrs.bar)
+      return () => (
+        // return a render function (both JSX and h() works)
+        <div>{props.foo}</div>
+      )
+    })
+    expectType<JSX.Element>(<MyComp foo={'1'} />)
+    // @ts-expect-error
+    expectType<JSX.Element>(<MyComp foo="1" bar={1} />)
+  })
+
   test('default attrs like class, style', () => {
     const MyComp = defineComponent({
       props: {

packages/runtime-core/src/apiDefineComponent.ts

@@ -24,12 +24,11 @@ import {
   ComponentObjectPropsOptions
 } from './componentProps'
 import { EmitsOptions, EmitsToProps } from './componentEmits'
-import { extend, isFunction } from '@vue/shared'
+import { IsSameType, extend, isFunction } from '@vue/shared'
 import { VNodeProps } from './vnode'
 import {
   CreateComponentPublicInstance,
-  ComponentPublicInstanceConstructor,
-  IsSameType
+  ComponentPublicInstanceConstructor
 } from './componentPublicInstance'
 import { SlotsType } from './componentSlots'
 
@@ -58,7 +57,7 @@ export type DefineComponent<
   Props = ResolveProps<PropsOrPropOptions, E>,
   Defaults = ExtractDefaultPropTypes<PropsOrPropOptions>,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 > = ComponentPublicInstanceConstructor<
   CreateComponentPublicInstance<
     Props,
@@ -108,8 +107,8 @@ export function defineComponent<
   E extends EmitsOptions = {},
   EE extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
-  PropsAttrs = IsSameType<undefined, Attrs> extends true
+  Attrs extends AttrsType = Record<string, unknown>,
+  PropsAttrs = IsSameType<string, keyof Attrs> extends true
     ? {}
     : UnwrapAttrsType<NonNullable<Attrs>>
 >(
@@ -155,7 +154,7 @@ export function defineComponent<
   E extends EmitsOptions = {},
   EE extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
+  Attrs extends AttrsType = Record<string, unknown>,
   I extends ComponentInjectOptions = {},
   II extends string = string
 >(
@@ -205,7 +204,7 @@ export function defineComponent<
   E extends EmitsOptions = {},
   EE extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
+  Attrs extends AttrsType = Record<string, unknown>,
   I extends ComponentInjectOptions = {},
   II extends string = string,
   Props = Readonly<{ [key in PropNames]?: any }>
@@ -259,7 +258,7 @@ export function defineComponent<
   S extends SlotsType = {},
   I extends ComponentInjectOptions = {},
   II extends string = string,
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 >(
   options: ComponentOptionsWithObjectProps<
     PropsOptions,

packages/runtime-core/src/component.ts

@@ -19,8 +19,7 @@ import {
   exposeSetupStateOnRenderContext,
   ComponentPublicInstanceConstructor,
   publicPropertiesMap,
-  RuntimeCompiledPublicInstanceProxyHandlers,
-  IsSameType
+  RuntimeCompiledPublicInstanceProxyHandlers
 } from './componentPublicInstance'
 import {
   ComponentPropsOptions,
@@ -67,7 +66,8 @@ import {
   ShapeFlags,
   extend,
   getGlobalThis,
-  IfAny
+  IfAny,
+  IsSameType
 } from '@vue/shared'
 import { SuspenseBoundary } from './components/Suspense'
 import { CompilerOptions } from '@vue/compiler-core'
@@ -188,10 +188,10 @@ type LifecycleHook<TFn = Function> = TFn[] | null
 export type SetupContext<
   E = EmitsOptions,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 > = E extends any
   ? {
-      attrs: IsSameType<Attrs, undefined> extends true
+      attrs: IsSameType<keyof Attrs, string> extends true
         ? Data
         : UnwrapAttrsType<NonNullable<Attrs>>
       slots: UnwrapSlotsType<S>

packages/runtime-core/src/componentOptions.ts

@@ -112,7 +112,7 @@ export interface ComponentOptionsBase<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 > extends LegacyOptions<Props, D, C, M, Mixin, Extends, I, II>,
     ComponentInternalOptions,
     ComponentCustomOptions {
@@ -226,7 +226,7 @@ export type ComponentOptionsWithoutProps<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
+  Attrs extends AttrsType = Record<string, unknown>,
   PE = Props & EmitsToProps<E>
 > = ComponentOptionsBase<
   PE,
@@ -277,7 +277,7 @@ export type ComponentOptionsWithArrayProps<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
+  Attrs extends AttrsType = Record<string, unknown>,
   Props = Prettify<Readonly<{ [key in PropNames]?: any } & EmitsToProps<E>>>
 > = ComponentOptionsBase<
   Props,
@@ -328,7 +328,7 @@ export type ComponentOptionsWithObjectProps<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
+  Attrs extends AttrsType = Record<string, unknown>,
   Props = Prettify<Readonly<ExtractPropTypes<PropsOptions> & EmitsToProps<E>>>,
   Defaults = ExtractDefaultPropTypes<PropsOptions>
 > = ComponentOptionsBase<

packages/runtime-core/src/componentPublicInstance.ts

@@ -16,7 +16,8 @@ import {
   isString,
   isFunction,
   UnionToIntersection,
-  Prettify
+  Prettify,
+  IsSameType
 } from '@vue/shared'
 import {
   toRaw,
@@ -152,7 +153,7 @@ export type CreateComponentPublicInstance<
   MakeDefaultsOptional extends boolean = false,
   I extends ComponentInjectOptions = {},
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
+  Attrs extends AttrsType = Record<string, unknown>,
   PublicMixin = IntersectionMixin<Mixin> & IntersectionMixin<Extends>,
   PublicP = UnwrapMixinsType<PublicMixin, 'P'> & EnsureNonVoid<P>,
   PublicB = UnwrapMixinsType<PublicMixin, 'B'> & EnsureNonVoid<B>,
@@ -194,12 +195,6 @@ export type CreateComponentPublicInstance<
   Attrs
 >
 
-export type IsSameType<T, U> = T extends U
-  ? U extends T
-    ? true
-    : false
-  : false
-
 // public properties exposed on the proxy, which is used as the render context
 // in templates (as `this` in the render option)
 export type ComponentPublicInstance<
@@ -215,8 +210,8 @@ export type ComponentPublicInstance<
   Options = ComponentOptionsBase<any, any, any, any, any, any, any, any, any>,
   I extends ComponentInjectOptions = {},
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined,
-  PropsAttrs = IsSameType<Attrs, undefined> extends true
+  Attrs extends AttrsType = Record<string, unknown>,
+  PropsAttrs = IsSameType<keyof Attrs, string> extends true
     ? {}
     : Omit<UnwrapAttrsType<NonNullable<Attrs>>, keyof (P & PublicProps)>
 > = {
@@ -227,7 +222,7 @@ export type ComponentPublicInstance<
       ? Partial<Defaults> & Omit<P & PublicProps, keyof Defaults> & PropsAttrs
       : P & PublicProps & PropsAttrs
   >
-  $attrs: IsSameType<Attrs, undefined> extends true
+  $attrs: IsSameType<keyof Attrs, string> extends true
     ? Data
     : Omit<UnwrapAttrsType<NonNullable<Attrs>>, keyof (P & PublicProps)> &
         AllowedComponentProps

packages/runtime-dom/src/apiCustomElement.ts

@@ -56,7 +56,7 @@ export function defineCustomElement<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 >(
   options: ComponentOptionsWithoutProps<
     Props,
@@ -89,7 +89,7 @@ export function defineCustomElement<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 >(
   options: ComponentOptionsWithArrayProps<
     PropNames,
@@ -122,7 +122,7 @@ export function defineCustomElement<
   I extends ComponentInjectOptions = {},
   II extends string = string,
   S extends SlotsType = {},
-  Attrs extends AttrsType | undefined = undefined
+  Attrs extends AttrsType = Record<string, unknown>
 >(
   options: ComponentOptionsWithObjectProps<
     PropsOptions,

packages/shared/src/typeUtils.ts

@@ -21,3 +21,9 @@ export type Awaited<T> = T extends null | undefined
     ? Awaited<V> // recursively unwrap the value
     : never // the argument to `then` was not callable
   : T // non-object or non-thenable
+
+export type IsSameType<T, U> = T extends U
+  ? U extends T
+    ? true
+    : false
+  : false