fix(vue-query): use distributive omit to preserve union

packages/vue-query/src/__tests__/test-utils.ts

@@ -50,3 +50,13 @@ export function successMutator<T>(param: T): Promise<T> {
 export function errorMutator<T>(_: T): Promise<Error> {
   return rejectFetcher()
 }
+
+export type Equal<X, Y> = (<T>() => T extends X ? 1 : 2) extends <
+  T,
+>() => T extends Y ? 1 : 2
+  ? true
+  : false
+
+export type Expect<T extends true> = T
+
+export const doNotExecute = (_func: () => void) => true

packages/vue-query/src/__tests__/useInfiniteQuery.types.test.tsx

@@ -0,0 +1,82 @@
+import { InfiniteData } from '@tanstack/query-core'
+import { reactive } from 'vue'
+import { useInfiniteQuery } from '../useInfiniteQuery'
+import { doNotExecute, Equal, Expect, simpleFetcher } from './test-utils'
+
+describe('Discriminated union return type', () => {
+  it('data should be possibly undefined by default', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useInfiniteQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      const result: Expect<
+        Equal<InfiniteData<string> | undefined, typeof query.data>
+      > = true
+      return result
+    })
+  })
+
+  it('data should be defined when query is success', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useInfiniteQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isSuccess) {
+        const result: Expect<Equal<InfiniteData<string>, typeof query.data>> =
+          true
+        return result
+      }
+    })
+  })
+
+  it('error should be null when query is success', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useInfiniteQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isSuccess) {
+        const result: Expect<Equal<null, typeof query.error>> = true
+        return result
+      }
+    })
+  })
+
+  it('data should be undefined when query is loading', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useInfiniteQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isLoading) {
+        const result: Expect<Equal<undefined, typeof query.data>> = true
+        return result
+      }
+    })
+  })
+
+  it('error should be defined when query is error', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useInfiniteQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isError) {
+        const result: Expect<Equal<unknown, typeof query.error>> = true
+        return result
+      }
+    })
+  })
+})

packages/vue-query/src/__tests__/useMutation.types.test.tsx

@@ -0,0 +1,69 @@
+import { reactive } from 'vue'
+import { useMutation } from '../useMutation'
+import { doNotExecute, Equal, Expect, successMutator } from './test-utils'
+
+describe('Discriminated union return type', () => {
+  it('data should be possibly undefined by default', () => {
+    doNotExecute(() => {
+      const mutation = reactive(
+        useMutation({ mutationFn: successMutator<string> }),
+      )
+
+      const result: Expect<Equal<string | undefined, typeof mutation.data>> =
+        true
+      return result
+    })
+  })
+
+  it('data should be defined when mutation is success', () => {
+    doNotExecute(() => {
+      const mutation = reactive(
+        useMutation({ mutationFn: successMutator<string> }),
+      )
+
+      if (mutation.isSuccess) {
+        const result: Expect<Equal<string, typeof mutation.data>> = true
+        return result
+      }
+    })
+  })
+
+  it('error should be null when mutation is success', () => {
+    doNotExecute(() => {
+      const mutation = reactive(
+        useMutation({ mutationFn: successMutator<string> }),
+      )
+
+      if (mutation.isSuccess) {
+        const result: Expect<Equal<null, typeof mutation.error>> = true
+        return result
+      }
+    })
+  })
+
+  it('data should be undefined when mutation is loading', () => {
+    doNotExecute(() => {
+      const mutation = reactive(
+        useMutation({ mutationFn: successMutator<string> }),
+      )
+
+      if (mutation.isLoading) {
+        const result: Expect<Equal<undefined, typeof mutation.data>> = true
+        return result
+      }
+    })
+  })
+
+  it('error should be defined when mutation is error', () => {
+    doNotExecute(() => {
+      const mutation = reactive(
+        useMutation({ mutationFn: successMutator<string> }),
+      )
+
+      if (mutation.isError) {
+        const result: Expect<Equal<unknown, typeof mutation.error>> = true
+        return result
+      }
+    })
+  })
+})

packages/vue-query/src/__tests__/useQuery.types.test.tsx

@@ -0,0 +1,78 @@
+import { reactive } from 'vue'
+import { useQuery } from '../useQuery'
+import { doNotExecute, Equal, Expect, simpleFetcher } from './test-utils'
+
+describe('Discriminated union return type', () => {
+  it('data should be possibly undefined by default', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      const result: Expect<Equal<string | undefined, typeof query.data>> = true
+      return result
+    })
+  })
+
+  it('data should be defined when query is success', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isSuccess) {
+        const result: Expect<Equal<string, typeof query.data>> = true
+        return result
+      }
+    })
+  })
+
+  it('error should be null when query is success', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isSuccess) {
+        const result: Expect<Equal<null, typeof query.error>> = true
+        return result
+      }
+    })
+  })
+
+  it('data should be undefined when query is loading', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isLoading) {
+        const result: Expect<Equal<undefined, typeof query.data>> = true
+        return result
+      }
+    })
+  })
+
+  it('error should be defined when query is error', () => {
+    doNotExecute(() => {
+      const query = reactive(
+        useQuery({
+          queryFn: simpleFetcher,
+        }),
+      )
+
+      if (query.isError) {
+        const result: Expect<Equal<unknown, typeof query.error>> = true
+        return result
+      }
+    })
+  })
+})

packages/vue-query/src/types.ts

@@ -92,3 +92,7 @@ export type VueInfiniteQueryObserverOptions<
         >[Property]
       >
 }
+
+export type DistributiveOmit<T, K extends keyof any> = T extends any
+  ? Omit<T, K>
+  : never

packages/vue-query/src/useInfiniteQuery.ts

@@ -13,6 +13,7 @@ import type { UseQueryReturnType } from './useBaseQuery'
 import type {
   WithQueryClientKey,
   VueInfiniteQueryObserverOptions,
+  DistributiveOmit,
 } from './types'
 
 export type UseInfiniteQueryOptions<
@@ -35,7 +36,7 @@ type InfiniteQueryReturnType<TData, TError> = UseQueryReturnType<
   TError,
   InfiniteQueryObserverResult<TData, TError>
 >
-export type UseInfiniteQueryReturnType<TData, TError> = Omit<
+export type UseInfiniteQueryReturnType<TData, TError> = DistributiveOmit<
   InfiniteQueryReturnType<TData, TError>,
   'fetchNextPage' | 'fetchPreviousPage' | 'refetch' | 'remove'
 > & {

packages/vue-query/src/useMutation.ts

@@ -16,12 +16,17 @@ import type {
   MutationObserverResult,
   MutationObserverOptions,
 } from '@tanstack/query-core'
-import type { WithQueryClientKey, MaybeRef, MaybeRefDeep } from './types'
+import type {
+  WithQueryClientKey,
+  MaybeRef,
+  MaybeRefDeep,
+  DistributiveOmit,
+} from './types'
 import { MutationObserver } from '@tanstack/query-core'
 import { cloneDeepUnref, updateState, isMutationKey } from './utils'
 import { useQueryClient } from './useQueryClient'
 
-type MutationResult<TData, TError, TVariables, TContext> = Omit<
+type MutationResult<TData, TError, TVariables, TContext> = DistributiveOmit<
   MutationObserverResult<TData, TError, TVariables, TContext>,
   'mutate' | 'reset'
 >

packages/vue-query/src/useQuery.ts

@@ -8,17 +8,21 @@ import type {
 } from '@tanstack/query-core'
 import { useBaseQuery } from './useBaseQuery'
 import type { UseQueryReturnType as UQRT } from './useBaseQuery'
-import type { WithQueryClientKey, VueQueryObserverOptions } from './types'
+import type {
+  WithQueryClientKey,
+  VueQueryObserverOptions,
+  DistributiveOmit,
+} from './types'
 
-export type UseQueryReturnType<TData, TError> = Omit<
+export type UseQueryReturnType<TData, TError> = DistributiveOmit<
   UQRT<TData, TError>,
   'refetch' | 'remove'
 > & {
   refetch: QueryObserverResult<TData, TError>['refetch']
   remove: QueryObserverResult<TData, TError>['remove']
 }
 
-export type UseQueryDefinedReturnType<TData, TError> = Omit<
+export type UseQueryDefinedReturnType<TData, TError> = DistributiveOmit<
   ToRefs<Readonly<DefinedQueryObserverResult<TData, TError>>>,
   'refetch' | 'remove'
 > & {