From 7046930a677f4c987afaee5a0165841b0e0a517f Mon Sep 17 00:00:00 2001
From: Maik Kowol <maik.s.kowol@gmail.com>
Date: Sun, 23 Jul 2023 10:24:54 +0200
Subject: [PATCH] fix(nuxt): add overloads for `asyncData` generic + default
 (#22258)

---
 .../nuxt/src/app/composables/asyncData.ts     | 43 +++++++++++++++++++
 packages/nuxt/src/app/composables/fetch.ts    | 26 +++++++++++
 test/fixtures/basic-types/types.ts            | 27 ++++++++++++
 3 files changed, 96 insertions(+)

diff --git a/packages/nuxt/src/app/composables/asyncData.ts b/packages/nuxt/src/app/composables/asyncData.ts
index 9cfad40dd4..817c7d0432 100644
--- a/packages/nuxt/src/app/composables/asyncData.ts
+++ b/packages/nuxt/src/app/composables/asyncData.ts
@@ -78,6 +78,16 @@ export function useAsyncData<
   handler: (ctx?: NuxtApp) => Promise<ResT>,
   options?: AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>
 ): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
+export function useAsyncData<
+  ResT,
+  DataE = Error,
+  DataT = ResT,
+  PickKeys extends KeysOf<DataT> = KeysOf<DataT>,
+  DefaultT = DataT,
+> (
+  handler: (ctx?: NuxtApp) => Promise<ResT>,
+  options?: AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>
+): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
 export function useAsyncData<
   ResT,
   DataE = Error,
@@ -89,6 +99,17 @@ export function useAsyncData<
   handler: (ctx?: NuxtApp) => Promise<ResT>,
   options?: AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>
 ): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
+export function useAsyncData<
+  ResT,
+  DataE = Error,
+  DataT = ResT,
+  PickKeys extends KeysOf<DataT> = KeysOf<DataT>,
+  DefaultT = DataT,
+> (
+  key: string,
+  handler: (ctx?: NuxtApp) => Promise<ResT>,
+  options?: AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>
+): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
 export function useAsyncData<
   ResT,
   DataE = Error,
@@ -267,6 +288,16 @@ export function useLazyAsyncData<
   handler: (ctx?: NuxtApp) => Promise<ResT>,
   options?: Omit<AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>, 'lazy'>
 ): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
+export function useLazyAsyncData<
+  ResT,
+  DataE = Error,
+  DataT = ResT,
+  PickKeys extends KeysOf<DataT> = KeysOf<DataT>,
+  DefaultT = DataT,
+> (
+  handler: (ctx?: NuxtApp) => Promise<ResT>,
+  options?: Omit<AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>, 'lazy'>
+): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
 export function useLazyAsyncData<
   ResT,
   DataE = Error,
@@ -278,6 +309,18 @@ export function useLazyAsyncData<
   handler: (ctx?: NuxtApp) => Promise<ResT>,
   options?: Omit<AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>, 'lazy'>
 ): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
+export function useLazyAsyncData<
+  ResT,
+  DataE = Error,
+  DataT = ResT,
+  PickKeys extends KeysOf<DataT> = KeysOf<DataT>,
+  DefaultT = DataT,
+> (
+  key: string,
+  handler: (ctx?: NuxtApp) => Promise<ResT>,
+  options?: Omit<AsyncDataOptions<ResT, DataT, PickKeys, DefaultT>, 'lazy'>
+): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, DataE | null>
+
 export function useLazyAsyncData<
   ResT,
   DataE = Error,
diff --git a/packages/nuxt/src/app/composables/fetch.ts b/packages/nuxt/src/app/composables/fetch.ts
index d838346d2c..11ea5aeffb 100644
--- a/packages/nuxt/src/app/composables/fetch.ts
+++ b/packages/nuxt/src/app/composables/fetch.ts
@@ -41,6 +41,19 @@ export function useFetch<
   request: Ref<ReqT> | ReqT | (() => ReqT),
   opts?: UseFetchOptions<_ResT, DataT, PickKeys, DefaultT, ReqT, Method>
 ): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, ErrorT | null>
+export function useFetch<
+  ResT = void,
+  ErrorT = FetchError,
+  ReqT extends NitroFetchRequest = NitroFetchRequest,
+  Method extends AvailableRouterMethod<ReqT> = ResT extends void ? 'get' extends AvailableRouterMethod<ReqT> ? 'get' : AvailableRouterMethod<ReqT> : AvailableRouterMethod<ReqT>,
+  _ResT = ResT extends void ? FetchResult<ReqT, Method> : ResT,
+  DataT = _ResT,
+  PickKeys extends KeysOf<DataT> = KeysOf<DataT>,
+  DefaultT = DataT,
+> (
+  request: Ref<ReqT> | ReqT | (() => ReqT),
+  opts?: UseFetchOptions<_ResT, DataT, PickKeys, DefaultT, ReqT, Method>
+): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, ErrorT | null>
 export function useFetch<
   ResT = void,
   ErrorT = FetchError,
@@ -136,6 +149,19 @@ export function useLazyFetch<
   request: Ref<ReqT> | ReqT | (() => ReqT),
   opts?: Omit<UseFetchOptions<_ResT, DataT, PickKeys, DefaultT, ReqT, Method>, 'lazy'>
 ): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, ErrorT | null>
+export function useLazyFetch<
+  ResT = void,
+  ErrorT = FetchError,
+  ReqT extends NitroFetchRequest = NitroFetchRequest,
+  Method extends AvailableRouterMethod<ReqT> = ResT extends void ? 'get' extends AvailableRouterMethod<ReqT> ? 'get' : AvailableRouterMethod<ReqT> : AvailableRouterMethod<ReqT>,
+  _ResT = ResT extends void ? FetchResult<ReqT, Method> : ResT,
+  DataT = _ResT,
+  PickKeys extends KeysOf<DataT> = KeysOf<DataT>,
+  DefaultT = DataT,
+> (
+  request: Ref<ReqT> | ReqT | (() => ReqT),
+  opts?: Omit<UseFetchOptions<_ResT, DataT, PickKeys, DefaultT, ReqT, Method>, 'lazy'>
+): AsyncData<PickFrom<DataT, PickKeys> | DefaultT, ErrorT | null>
 export function useLazyFetch<
   ResT = void,
   ErrorT = FetchError,
diff --git a/test/fixtures/basic-types/types.ts b/test/fixtures/basic-types/types.ts
index e28585cedc..74d9868a90 100644
--- a/test/fixtures/basic-types/types.ts
+++ b/test/fixtures/basic-types/types.ts
@@ -309,6 +309,33 @@ describe('composables', () => {
     expectTypeOf(useFetch('/test', { default: () => 500 }).data).toEqualTypeOf<Ref<unknown>>()
   })
 
+  it('correct types when using ResT type-assertion with default function', () => {
+    // @ts-expect-error default type should match generic type
+    useFetch<string>('/test', { default: () => 0 })
+    // @ts-expect-error default type should match generic type
+    useLazyFetch<string>('/test', { default: () => 0 })
+    // @ts-expect-error default type should match generic type
+    useAsyncData<string>(() => $fetch('/test'), { default: () => 0 })
+    // @ts-expect-error default type should match generic type
+    useLazyAsyncData<string>(() => $fetch('/test'), { default: () => 0 })
+
+    expectTypeOf(useFetch<string>('/test', { default: () => 'test' }).data).toEqualTypeOf<Ref<string>>()
+    expectTypeOf(useLazyFetch<string>('/test', { default: () => 'test' }).data).toEqualTypeOf<Ref<string>>()
+    expectTypeOf(useAsyncData<string>(() => $fetch('/test'), { default: () => 'test' }).data).toEqualTypeOf<Ref<string>>()
+    expectTypeOf(useLazyAsyncData<string>(() => $fetch('/test'), { default: () => 'test' }).data).toEqualTypeOf<Ref<string>>()
+
+    // transform must match the explicit generic because of typescript limiations microsoft/TypeScript#14400
+    expectTypeOf(useFetch<string>('/test', { transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string | null>>()
+    expectTypeOf(useLazyFetch<string>('/test', { transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string | null>>()
+    expectTypeOf(useAsyncData<string>(() => $fetch('/test'), { transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string | null>>()
+    expectTypeOf(useLazyAsyncData<string>(() => $fetch('/test'), { transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string | null>>()
+
+    expectTypeOf(useFetch<string>('/test', { default: () => 'test', transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string>>()
+    expectTypeOf(useLazyFetch<string>('/test', { default: () => 'test', transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string>>()
+    expectTypeOf(useAsyncData<string>(() => $fetch('/test'), { default: () => 'test', transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string>>()
+    expectTypeOf(useLazyAsyncData<string>(() => $fetch('/test'), { default: () => 'test', transform: () => 'transformed' }).data).toEqualTypeOf<Ref<string>>()
+  })
+
   it('infer request url string literal from server/api routes', () => {
     // request can accept dynamic string type
     const dynamicStringUrl = 'https://example.com/api'