From 9a7c76870e4bdc806e44de06e86abe3c2e40fb56 Mon Sep 17 00:00:00 2001
From: Yixuan Xu <yixuanxu94@outlook.com>
Date: Wed, 6 Apr 2022 21:44:10 +0800
Subject: [PATCH] type: make type inference simpler (#1908)

---
 infinite/types.ts           |  4 +---
 src/types.ts                |  6 +-----
 test/type/fetcher.ts        |  8 ++++----
 test/type/option-fetcher.ts | 10 +++++-----
 4 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/infinite/types.ts b/infinite/types.ts
index 7cfd0d3a6..b714c1a17 100644
--- a/infinite/types.ts
+++ b/infinite/types.ts
@@ -6,9 +6,7 @@ export type SWRInfiniteFetcher<
   Data = any,
   KeyLoader extends SWRInfiniteKeyLoader = SWRInfiniteKeyLoader
 > = KeyLoader extends (...args: any[]) => any
-  ? ReturnType<KeyLoader> extends readonly [...infer T]
-    ? (args: T) => FetcherResponse<Data>
-    : ReturnType<KeyLoader> extends infer T | null | false | undefined
+  ? ReturnType<KeyLoader> extends infer T | null | false | undefined
     ? (args: T) => FetcherResponse<Data>
     : never
   : never
diff --git a/src/types.ts b/src/types.ts
index 4c42b0040..e76ddf8d3 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -7,11 +7,7 @@ export type BareFetcher<Data = unknown> = (
 export type Fetcher<
   Data = unknown,
   SWRKey extends Key = Key
-> = SWRKey extends () => readonly [...infer Args]
-  ? (args: Args) => FetcherResponse<Data>
-  : SWRKey extends readonly [...infer Args]
-  ? (args: Args) => FetcherResponse<Data>
-  : SWRKey extends () => infer Arg | null | undefined | false
+> = SWRKey extends () => infer Arg | null | undefined | false
   ? (args: Arg) => FetcherResponse<Data>
   : SWRKey extends null | undefined | false
   ? never
diff --git a/test/type/fetcher.ts b/test/type/fetcher.ts
index e1b1ebb4a..c439ed28c 100644
--- a/test/type/fetcher.ts
+++ b/test/type/fetcher.ts
@@ -78,7 +78,7 @@ export function useTuple() {
 export function useReadonlyTuple() {
   useSWR([{ a: '1', b: { c: '3' } }, [1231, '888']] as const, keys => {
     expectType<
-      [
+      readonly [
         {
           readonly a: '1'
           readonly b: {
@@ -94,7 +94,7 @@ export function useReadonlyTuple() {
     truthy() ? ([{ a: '1', b: { c: '3' } }, [1231, '888']] as const) : null,
     keys => {
       expectType<
-        [
+        readonly [
           {
             readonly a: '1'
             readonly b: {
@@ -111,7 +111,7 @@ export function useReadonlyTuple() {
     truthy() ? ([{ a: '1', b: { c: '3' } }, [1231, '888']] as const) : false,
     keys => {
       expectType<
-        [
+        readonly [
           {
             readonly a: '1'
             readonly b: {
@@ -300,7 +300,7 @@ export function useReturnReadonlyTuple() {
     () => [{ a: '1', b: { c: '3' } }, [1231, '888']] as const,
     keys => {
       expectType<
-        [
+        readonly [
           {
             readonly a: '1'
             readonly b: {
diff --git a/test/type/option-fetcher.ts b/test/type/option-fetcher.ts
index 4e34a19ac..1b9bd0b8b 100644
--- a/test/type/option-fetcher.ts
+++ b/test/type/option-fetcher.ts
@@ -80,7 +80,7 @@ export function useReadonlyTuple() {
   useSWR([{ a: '1', b: { c: '3' } }, [1231, '888']] as const, {
     fetcher: keys => {
       expectType<
-        [
+        readonly [
           {
             readonly a: '1'
             readonly b: {
@@ -98,7 +98,7 @@ export function useReadonlyTuple() {
     {
       fetcher: keys => {
         expectType<
-          [
+          readonly [
             {
               readonly a: '1'
               readonly b: {
@@ -117,7 +117,7 @@ export function useReadonlyTuple() {
     {
       fetcher: keys => {
         expectType<
-          [
+          readonly [
             {
               readonly a: '1'
               readonly b: {
@@ -318,7 +318,7 @@ export function useReturnReadonlyTuple() {
   useSWR(() => [{ a: '1', b: { c: '3' } }, [1231, '888']] as const, {
     fetcher: keys => {
       expectType<
-        [
+        readonly [
           {
             readonly a: '1'
             readonly b: {
@@ -376,7 +376,7 @@ export function useReturnReadonlyTuple() {
   useSWRInfinite(() => [{ a: '1', b: { c: '3' } }, [1231, '888']] as const, {
     fetcher: keys => {
       expectType<
-        [
+        readonly [
           {
             readonly a: '1'
             readonly b: {