type fetcher

infinite/index.ts

@@ -5,10 +5,11 @@ import { useRef, useState, useCallback } from 'react'
 import useSWR, {
   SWRConfig,
   KeyLoader,
-  Fetcher,
   SWRHook,
   MutatorCallback,
-  Middleware
+  Middleware,
+  Result,
+  ValueKey
 } from 'swr'
 import { useIsomorphicLayoutEffect } from '../src/utils/env'
 import { serialize } from '../src/utils/serialize'
@@ -246,20 +247,56 @@ export const infinite = ((<Data, Error>(useSWRNext: SWRHook) => (
   } as SWRInfiniteResponse<Data, Error>
 }) as unknown) as Middleware
 
-type SWRInfiniteHook = <Data = any, Error = any>(
-  ...args:
-    | readonly [KeyLoader<Data>]
-    | readonly [KeyLoader<Data>, Fetcher<Data> | null]
-    | readonly [
-        KeyLoader<Data>,
-        SWRInfiniteConfiguration<Data, Error> | undefined
-      ]
-    | readonly [
-        KeyLoader<Data>,
-        Fetcher<Data> | null,
-        SWRInfiniteConfiguration<Data, Error> | undefined
-      ]
-) => SWRInfiniteResponse<Data, Error>
-
-export default withMiddleware(useSWR, infinite) as SWRInfiniteHook
+type Fetcher<Data = unknown, Args extends ValueKey = ValueKey> = Args extends
+  | [infer R, ...infer K]
+  | readonly [infer R, ...infer K]
+  ? (...args: [R, ...K]) => Result<Data>
+  : Args extends string | null
+  ? (...args: [string]) => Result<Data>
+  : Args extends Record<infer K, infer V>
+  ? (...args: [Record<K, V>]) => Result<Data>
+  : never
+
+interface SWRInfiniteHook {
+  <Data = any, Error = any, Args extends ValueKey = ValueKey>(
+    args: KeyLoader<Data, Args>
+  ): SWRInfiniteResponse<Data, Error>
+  <Data = any, Error = any, Args extends ValueKey = ValueKey>(
+    args: KeyLoader<Data, Args>,
+    fn: Fetcher<Data, Args> | null
+  ): SWRInfiniteResponse<Data, Error>
+  <Data = any, Error = any, Args extends ValueKey = ValueKey>(
+    args: KeyLoader<Data, Args>,
+    config:
+      | SWRInfiniteConfiguration<Data, Error, Args, Fetcher<Data[], Args>>
+      | undefined
+  ): SWRInfiniteResponse<Data, Error>
+  <Data = any, Error = any, Args extends ValueKey = ValueKey>(
+    args: KeyLoader<Data, Args>,
+    fn: Fetcher<Data, Args>,
+    config: SWRInfiniteConfiguration<Data, Error, Args, Fetcher<Data[], Args>>
+  ): SWRInfiniteResponse<Data, Error>
+  <Data = any, Error = any, Args extends ValueKey = ValueKey>(
+    ...args:
+      | [KeyLoader<Data, Args>]
+      | [KeyLoader<Data, Args>, Fetcher<Data, Args> | null]
+      | [
+          KeyLoader<Data, Args>,
+
+
+            | SWRInfiniteConfiguration<Data, Error, Args, Fetcher<Data[], Args>>
+            | undefined
+        ]
+      | [
+          KeyLoader<Data, Args>,
+          Fetcher<Data, Args> | null,
+
+
+            | SWRInfiniteConfiguration<Data, Error, Args, Fetcher<Data[], Args>>
+            | undefined
+        ]
+  ): SWRInfiniteResponse<Data, Error>
+}
+
+export default (withMiddleware(useSWR, infinite) as unknown) as SWRInfiniteHook
 export { SWRInfiniteConfiguration, SWRInfiniteResponse }

infinite/types.ts

@@ -1,9 +1,11 @@
-import { SWRConfiguration, Fetcher, SWRResponse } from 'swr'
+import { SWRConfiguration, Fetcher, SWRResponse, ValueKey } from 'swr'
 
 export type SWRInfiniteConfiguration<
   Data = any,
-  Error = any
-> = SWRConfiguration<Data[], Error, Fetcher<Data[]>> & {
+  Error = any,
+  Args extends ValueKey = ValueKey,
+  Fn = Fetcher<any, Args>
+> = SWRConfiguration<Data[], Error, Args, Fn> & {
   initialSize?: number
   revalidateAll?: boolean
   persistSize?: boolean

package.json

@@ -71,8 +71,8 @@
     "@testing-library/jest-dom": "5.14.1",
     "@testing-library/react": "12.0.0",
     "@types/react": "17.0.20",
-    "@typescript-eslint/eslint-plugin": "4.24.0",
-    "@typescript-eslint/parser": "4.24.0",
+    "@typescript-eslint/eslint-plugin": "4.31.1",
+    "@typescript-eslint/parser": "4.31.1",
     "bunchee": "1.7.1",
     "eslint": "6.6.0",
     "eslint-config-prettier": "6.5.0",
@@ -91,7 +91,7 @@
     "react-experimental": "npm:react@alpha",
     "rimraf": "3.0.2",
     "ts-jest": "27.0.3",
-    "typescript": "3.9.10"
+    "typescript": "4.4.3"
   },
   "peerDependencies": {
     "react": "^16.11.0 || ^17.0.0 || ^18.0.0"

src/index.ts

@@ -20,5 +20,7 @@ export {
   SWRHook,
   Fetcher,
   MutatorCallback,
-  Middleware
+  Middleware,
+  ValueKey,
+  Result
 } from './types'

src/types.ts

@@ -1,6 +1,23 @@
 import * as revalidateEvents from './constants/revalidate-events'
 
-export type Fetcher<Data> = (...args: any) => Data | Promise<Data>
+export type Result<T = unknown> = T | Promise<T>
+
+export type Fetcher<
+  Data = unknown,
+  Args extends Key = Key
+> = Args extends (() => [infer R, ...infer K] | readonly [infer R, ...infer K])
+  ? ((...args: [R, ...K]) => Result<Data>)
+  : Args extends [infer R, ...infer K] | readonly [infer R, ...infer K]
+  ? ((...args: [R, ...K]) => Result<Data>)
+  : Args extends (() => string | null)
+  ? (...args: [string]) => Result<Data>
+  : Args extends string | null
+  ? (...args: [string]) => Result<Data>
+  : Args extends () => Record<infer K, infer V>
+  ? (...args: [Record<K, V>]) => Result<Data>
+  : Args extends Record<infer K, infer V>
+  ? (...args: [Record<K, V>]) => Result<Data>
+  : never
 
 // Configuration types that are only used internally, not exposed to the user.
 export interface InternalConfiguration {
@@ -11,7 +28,8 @@ export interface InternalConfiguration {
 export interface PublicConfiguration<
   Data = any,
   Error = any,
-  Fn extends Fetcher<Data> = Fetcher<Data>
+  Args extends Key = Key,
+  Fn = Fetcher<Data, Args>
 > {
   errorRetryInterval: number
   errorRetryCount?: number
@@ -35,22 +53,22 @@ export interface PublicConfiguration<
   isPaused: () => boolean
   onLoadingSlow: (
     key: string,
-    config: Readonly<PublicConfiguration<Data, Error>>
+    config: Readonly<PublicConfiguration<Data, Error, Args, Fn>>
   ) => void
   onSuccess: (
     data: Data,
     key: string,
-    config: Readonly<PublicConfiguration<Data, Error>>
+    config: Readonly<PublicConfiguration<Data, Error, Args, Fn>>
   ) => void
   onError: (
     err: Error,
     key: string,
-    config: Readonly<PublicConfiguration<Data, Error>>
+    config: Readonly<PublicConfiguration<Data, Error, Args, Fn>>
   ) => void
   onErrorRetry: (
     err: Error,
     key: string,
-    config: Readonly<PublicConfiguration<Data, Error>>,
+    config: Readonly<PublicConfiguration<Data, Error, Args, Fn>>,
     revalidate: Revalidator,
     revalidateOpts: Required<RevalidatorOptions>
   ) => void
@@ -67,29 +85,51 @@ export type ConfigOptions = {
   initFocus: (callback: () => void) => (() => void) | void
   initReconnect: (callback: () => void) => (() => void) | void
 }
-
-export type SWRHook = <Data = any, Error = any>(
-  ...args:
-    | readonly [Key]
-    | readonly [Key, Fetcher<Data> | null]
-    | readonly [Key, SWRConfiguration<Data, Error> | undefined]
-    | readonly [
-        Key,
-        Fetcher<Data> | null,
-        SWRConfiguration<Data, Error> | undefined
-      ]
-) => SWRResponse<Data, Error>
+export interface SWRHook {
+  <Data = any, Error = any, Args extends Key = Key>(args: Args): SWRResponse<
+    Data,
+    Error
+  >
+  <Data = any, Error = any, Args extends Key = Key>(
+    args: Args,
+    fn: Fetcher<Data, Args> | null
+  ): SWRResponse<Data, Error>
+  <Data = any, Error = any, Args extends Key = Key>(
+    args: Args,
+    config: SWRConfiguration<Data, Error, Args, Fetcher<Data, Args>> | undefined
+  ): SWRResponse<Data, Error>
+  <Data = any, Error = any, Args extends Key = Key>(
+    args: Args,
+    fn: Fetcher<Data, Args>,
+    config: SWRConfiguration<Data, Error, Args, Fetcher<Data, Args>>
+  ): SWRResponse<Data, Error>
+  <Data = any, Error = any, Args extends Key = Key>(
+    ...args:
+      | [Args]
+      | [Args, Fetcher<Data, Args> | null]
+      | [
+          Args,
+          SWRConfiguration<Data, Error, Args, Fetcher<Data, Args>> | undefined
+        ]
+      | [
+          Args,
+          Fetcher<Data, Key> | null,
+          SWRConfiguration<Data, Error, Args, Fetcher<Data, Args>>
+        ]
+  ): SWRResponse<Data, Error>
+}
 
 // Middlewares guarantee that a SWRHook receives a key, fetcher, and config as the argument
 type SWRHookWithMiddleware = <Data = any, Error = any>(
   key: Key,
-  fetcher: Fetcher<Data> | null,
+  fetcher: Fetcher<Data, Key> | null,
   config: SWRConfiguration<Data, Error>
 ) => SWRResponse<Data, Error>
 
 export type Middleware = (useSWRNext: SWRHook) => SWRHookWithMiddleware
-
-export type ValueKey = string | any[] | object | null
+export type TupleKey = [any, ...unknown[]] | readonly [any, ...unknown[]]
+export type ValueKey = string | null | TupleKey | Record<any, any>
+export type Key = ValueKey | (() => ValueKey)
 
 export type MutatorCallback<Data = any> = (
   currentValue?: Data
@@ -142,10 +182,9 @@ export type KeyedMutator<Data> = (
 export type SWRConfiguration<
   Data = any,
   Error = any,
-  Fn extends Fetcher<Data> = Fetcher<Data>
-> = Partial<PublicConfiguration<Data, Error, Fn>>
-
-export type Key = ValueKey | (() => ValueKey)
+  Args extends Key = Key,
+  Fn = Fetcher<any, Args>
+> = Partial<PublicConfiguration<Data, Error, Args, Fn>>
 
 export interface SWRResponse<Data, Error> {
   data?: Data
@@ -154,9 +193,10 @@ export interface SWRResponse<Data, Error> {
   isValidating: boolean
 }
 
-export type KeyLoader<Data = any> =
-  | ((index: number, previousPageData: Data | null) => ValueKey)
+export type KeyLoader<Data = any, Args extends ValueKey = ValueKey> =
+  | ((index: number, previousPageData: Data | null) => Args)
   | null
+
 export interface RevalidatorOptions {
   retryCount?: number
   dedupe?: boolean

src/use-swr.ts

@@ -175,7 +175,8 @@ export const useSWRHandler = <Data = any, Error = any>(
 
           // Start the request and keep the timestamp.
           CONCURRENT_PROMISES_TS[key] = startAt = getTimestamp()
-          newData = await (CONCURRENT_PROMISES[key] = fn.apply(fn, fnArgs))
+          // @ts-ignore FIXME When September ends
+          newData = await (CONCURRENT_PROMISES[key] = fn(...fnArgs))
 
           setTimeout(() => {
             // CONCURRENT_PROMISES_TS[key] maybe be `undefined` or a number.

src/utils/normalize-args.ts

@@ -4,10 +4,10 @@ import { Key, Fetcher, SWRConfiguration } from '../types'
 
 export const normalize = <KeyType = Key, Data = any>(
   args:
-    | readonly [KeyType]
-    | readonly [KeyType, Fetcher<Data> | null]
-    | readonly [KeyType, SWRConfiguration | undefined]
-    | readonly [KeyType, Fetcher<Data> | null, SWRConfiguration | undefined]
+    | [KeyType]
+    | [KeyType, Fetcher<Data> | null]
+    | [KeyType, SWRConfiguration | undefined]
+    | [KeyType, Fetcher<Data> | null, SWRConfiguration | undefined]
 ): [KeyType, Fetcher<Data> | null, Partial<SWRConfiguration<Data>>] => {
   return isFunction(args[1])
     ? [args[0], args[1], args[2] || {}]

src/utils/serialize.ts

@@ -3,7 +3,7 @@ import { isFunction } from './helper'
 
 import { Key } from '../types'
 
-export const serialize = (key: Key): [string, any, string, string] => {
+export const serialize = (key: Key): [string, any[], string, string] => {
   if (isFunction(key)) {
     try {
       key = key()

src/utils/with-middleware.ts

@@ -9,10 +9,10 @@ export const withMiddleware = (
 ): SWRHook => {
   return <Data = any, Error = any>(
     ...args:
-      | readonly [Key]
-      | readonly [Key, Fetcher<Data> | null]
-      | readonly [Key, SWRConfiguration | undefined]
-      | readonly [Key, Fetcher<Data> | null, SWRConfiguration | undefined]
+      | [Key]
+      | [Key, Fetcher<Data> | null]
+      | [Key, SWRConfiguration | undefined]
+      | [Key, Fetcher<Data> | null, SWRConfiguration | undefined]
   ) => {
     const [key, fn, config] = normalize(args)
     config.use = (config.use || []).concat(middleware)