chore: improve code readability

Author: rudyxu1102

packages/runtime-core/src/apiDefineComponent.ts

@@ -15,7 +15,8 @@ import {
 import {
   SetupContext,
   AllowedComponentProps,
-  ComponentCustomProps
+  ComponentCustomProps,
+  HasDefineAttrs
 } from './component'
 import {
   ExtractPropTypes,
@@ -24,7 +25,7 @@ import {
   ComponentObjectPropsOptions
 } from './componentProps'
 import { EmitsOptions, EmitsToProps } from './componentEmits'
-import { IsSameType, extend, isFunction } from '@vue/shared'
+import { extend, isFunction } from '@vue/shared'
 import { VNodeProps } from './vnode'
 import {
   CreateComponentPublicInstance,
@@ -108,7 +109,7 @@ export function defineComponent<
   EE extends string = string,
   S extends SlotsType = {},
   Attrs extends AttrsType = Record<string, unknown>,
-  PropsAttrs = IsSameType<string, keyof Attrs> extends true
+  PropsAttrs = HasDefineAttrs<Attrs> extends true
     ? {}
     : UnwrapAttrsType<NonNullable<Attrs>>
 >(

packages/runtime-core/src/component.ts

@@ -67,7 +67,7 @@ import {
   extend,
   getGlobalThis,
   IfAny,
-  IsSameType
+  Equal
 } from '@vue/shared'
 import { SuspenseBoundary } from './components/Suspense'
 import { CompilerOptions } from '@vue/compiler-core'
@@ -84,7 +84,7 @@ import { SchedulerJob } from './scheduler'
 import { LifecycleHooks } from './enums'
 
 export type Data = Record<string, unknown>
-
+export type HasDefineAttrs<T> = Equal<keyof T, string>
 /**
  * For extending allowed non-declared props on components in TSX
  */
@@ -191,7 +191,7 @@ export type SetupContext<
   Attrs extends AttrsType = Record<string, unknown>
 > = E extends any
   ? {
-      attrs: IsSameType<keyof Attrs, string> extends true
+      attrs: HasDefineAttrs<Attrs> extends true
         ? Data
         : UnwrapAttrsType<NonNullable<Attrs>>
       slots: UnwrapSlotsType<S>

packages/runtime-core/src/componentPublicInstance.ts

@@ -2,6 +2,7 @@ import {
   AllowedComponentProps,
   ComponentInternalInstance,
   Data,
+  HasDefineAttrs,
   getExposeProxy,
   isStatefulComponent
 } from './component'
@@ -16,8 +17,7 @@ import {
   isString,
   isFunction,
   UnionToIntersection,
-  Prettify,
-  IsSameType
+  Prettify
 } from '@vue/shared'
 import {
   toRaw,
@@ -211,9 +211,9 @@ export type ComponentPublicInstance<
   I extends ComponentInjectOptions = {},
   S extends SlotsType = {},
   Attrs extends AttrsType = Record<string, unknown>,
-  PropsAttrs = IsSameType<keyof Attrs, string> extends true
+  PropsAttrs = HasDefineAttrs<Attrs> extends true
     ? {}
-    : Omit<UnwrapAttrsType<NonNullable<Attrs>>, keyof (P & PublicProps)>
+    : Omit<UnwrapAttrsType<Attrs>, keyof (P & PublicProps)>
 > = {
   $: ComponentInternalInstance
   $data: D
@@ -222,9 +222,9 @@ export type ComponentPublicInstance<
       ? Partial<Defaults> & Omit<P & PublicProps, keyof Defaults> & PropsAttrs
       : P & PublicProps & PropsAttrs
   >
-  $attrs: IsSameType<keyof Attrs, string> extends true
+  $attrs: HasDefineAttrs<Attrs> extends true
     ? Data
-    : Omit<UnwrapAttrsType<NonNullable<Attrs>>, keyof (P & PublicProps)> &
+    : Omit<UnwrapAttrsType<Attrs>, keyof (P & PublicProps)> &
         AllowedComponentProps
   $refs: Data
   $slots: UnwrapSlotsType<S>

packages/shared/src/typeUtils.ts

@@ -22,8 +22,8 @@ export type Awaited<T> = T extends null | undefined
     : 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
+// Conditional returns can enforce identical types.
+// See here: https://github.com/Microsoft/TypeScript/issues/27024#issuecomment-421529650
+// prettier-ignore
+export type Equal<Left, Right> =
+(<U>() => U extends Left ? 1 : 0) extends (<U>() => U extends Right ? 1 : 0) ? true : false;