feat: Hook for remote mutations

examples/axios-typescript/libs/useRequest.ts

@@ -24,10 +24,12 @@ export default function useRequest<Data = unknown, Error = unknown>(
   request: GetRequest,
   { fallbackData, ...config }: Config<Data, Error> = {}
 ): Return<Data, Error> {
-  const { data: response, error, isValidating, mutate } = useSWR<
-    AxiosResponse<Data>,
-    AxiosError<Error>
-  >(
+  const {
+    data: response,
+    error,
+    isValidating,
+    mutate
+  } = useSWR<AxiosResponse<Data>, AxiosError<Error>>(
     request && JSON.stringify(request),
     /**
      * NOTE: Typescript thinks `request` can be `null` here, but the fetcher

jest.config.js

@@ -6,7 +6,8 @@ module.exports = {
   moduleNameMapper: {
     '^swr$': '<rootDir>/src',
     '^swr/infinite$': '<rootDir>/infinite/index.ts',
-    '^swr/immutable$': '<rootDir>/immutable/index.ts'
+    '^swr/immutable$': '<rootDir>/immutable/index.ts',
+    '^swr/mutation$': '<rootDir>/mutation/index.ts'
   },
   transform: {
     '^.+\\.(t|j)sx?$': '@swc/jest'

mutation/index.ts

@@ -0,0 +1,122 @@
+import { useCallback, useRef } from 'react'
+import useSWR, { useSWRConfig, Middleware, Key } from 'swr'
+
+import { serialize } from '../src/utils/serialize'
+import { useStateWithDeps } from '../src/utils/state'
+import { withMiddleware } from '../src/utils/with-middleware'
+import { useIsomorphicLayoutEffect } from '../src/utils/env'
+import { UNDEFINED } from '../src/utils/helper'
+import { getTimestamp } from '../src/utils/timestamp'
+
+import {
+  SWRMutationConfiguration,
+  SWRMutationResponse,
+  SWRMutationHook,
+  MutationFetcher
+} from './types'
+
+const mutation =
+  <Data, Error>() =>
+  (
+    key: Key,
+    fetcher: MutationFetcher<Data>,
+    config: SWRMutationConfiguration<Data, Error> = {}
+  ) => {
+    const { mutate } = useSWRConfig()
+
+    const keyRef = useRef(key)
+    // Ditch all mutation results that happened earlier than this timestamp.
+    const ditchMutationsUntilRef = useRef(0)
+
+    const [stateRef, stateDependencies, setState] = useStateWithDeps({
+      data: UNDEFINED,
+      error: UNDEFINED,
+      isMutating: false
+    })
+    const currentState = stateRef.current
+
+    const trigger = useCallback(
+      async (arg, opts?: SWRMutationConfiguration<Data, Error>) => {
+        const [serializedKey, resolvedKey] = serialize(keyRef.current)
+
+        if (!fetcher) {
+          throw new Error('Can’t trigger the mutation: missing fetcher.')
+        }
+        if (!serializedKey) {
+          throw new Error('Can’t trigger the mutation: key isn’t ready.')
+        }
+
+        // Disable cache population by default.
+        const options = Object.assign({ populateCache: false }, config, opts)
+
+        // Trigger a mutation, also track the timestamp. Any mutation that happened
+        // earlier this timestamp should be ignored.
+        const mutationStartedAt = getTimestamp()
+
+        ditchMutationsUntilRef.current = mutationStartedAt
+
+        setState({ isMutating: true })
+
+        try {
+          const data = await mutate<Data>(
+            serializedKey,
+            (fetcher as any)(resolvedKey, { arg }),
+            options
+          )
+
+          // If it's reset after the mutation, we don't broadcast any state change.
+          if (ditchMutationsUntilRef.current <= mutationStartedAt) {
+            setState({ data, isMutating: false })
+            options.onSuccess?.(data as Data, serializedKey, options)
+          }
+          return data
+        } catch (error) {
+          // If it's reset after the mutation, we don't broadcast any state change.
+          if (ditchMutationsUntilRef.current <= mutationStartedAt) {
+            setState({ error: error as Error, isMutating: false })
+            options.onError?.(error as Error, serializedKey, options)
+            throw error as Error
+          }
+        }
+      },
+      // eslint-disable-next-line react-hooks/exhaustive-deps
+      []
+    )
+
+    const reset = useCallback(() => {
+      ditchMutationsUntilRef.current = getTimestamp()
+      setState({ data: UNDEFINED, error: UNDEFINED, isMutating: false })
+      // eslint-disable-next-line react-hooks/exhaustive-deps
+    }, [])
+
+    useIsomorphicLayoutEffect(() => {
+      keyRef.current = key
+    })
+
+    // We don't return `mutate` here as it can be pretty confusing (e.g. people
+    // calling `mutate` but they actually mean `trigger`).
+    // And also, `mutate` relies on the useSWR hook to exist too.
+    return {
+      trigger,
+      reset,
+      get data() {
+        stateDependencies.data = true
+        return currentState.data
+      },
+      get error() {
+        stateDependencies.error = true
+        return currentState.error
+      },
+      get isMutating() {
+        stateDependencies.isMutating = true
+        return currentState.isMutating
+      }
+    }
+  }
+
+export default withMiddleware(
+  useSWR,
+  mutation as unknown as Middleware
+) as unknown as SWRMutationHook
+
+export { SWRMutationConfiguration, SWRMutationResponse }

mutation/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "swr-mutation",
+  "version": "0.0.1",
+  "main": "./dist/index.js",
+  "module": "./dist/index.esm.js",
+  "types": "./dist/mutation",
+  "peerDependencies": {
+    "swr": "*",
+    "react": "*"
+  }
+}

mutation/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "..",
+    "outDir": "./dist"
+  },
+  "include": ["./*.ts"]
+}

mutation/types.ts

@@ -0,0 +1,71 @@
+import { SWRResponse, Key, MutatorOptions } from 'swr'
+
+type FetcherResponse<Data> = Data | Promise<Data>
+
+type FetcherOptions<ExtraArg = unknown> = Readonly<{
+  arg: ExtraArg
+}>
+
+export type MutationFetcher<
+  Data = unknown,
+  ExtraArg = unknown,
+  SWRKey extends Key = Key
+> = SWRKey extends () => infer Arg | null | undefined | false
+  ? (key: Arg, options: FetcherOptions<ExtraArg>) => FetcherResponse<Data>
+  : SWRKey extends null | undefined | false
+  ? never
+  : SWRKey extends infer Arg
+  ? (key: Arg, options: FetcherOptions<ExtraArg>) => FetcherResponse<Data>
+  : never
+
+export type SWRMutationConfiguration<
+  Data,
+  Error,
+  ExtraArg = any,
+  SWRMutationKey extends Key = Key
+> = MutatorOptions<Data> & {
+  fetcher?: MutationFetcher<Data, ExtraArg, SWRMutationKey>
+  onSuccess?: (
+    data: Data,
+    key: string,
+    config: Readonly<
+      SWRMutationConfiguration<Data, Error, SWRMutationKey, ExtraArg>
+    >
+  ) => void
+  onError?: (
+    err: Error,
+    key: string,
+    config: Readonly<
+      SWRMutationConfiguration<Data, Error, SWRMutationKey, ExtraArg>
+    >
+  ) => void
+}
+
+export interface SWRMutationResponse<
+  Data = any,
+  Error = any,
+  ExtraArg = any,
+  SWRMutationKey extends Key = Key
+> extends Pick<SWRResponse<Data, Error>, 'data' | 'error'> {
+  isMutating: boolean
+  trigger: (
+    extraArgument?: ExtraArg,
+    options?: SWRMutationConfiguration<Data, Error, ExtraArg, SWRMutationKey>
+  ) => Promise<Data | undefined>
+  reset: () => void
+}
+
+export type SWRMutationHook = <
+  Data = any,
+  Error = any,
+  SWRMutationKey extends Key = Key,
+  ExtraArg = any
+>(
+  ...args:
+    | readonly [SWRMutationKey, MutationFetcher<Data, ExtraArg, SWRMutationKey>]
+    | readonly [
+        SWRMutationKey,
+        MutationFetcher<Data, ExtraArg, SWRMutationKey>,
+        SWRMutationConfiguration<Data, Error, ExtraArg, SWRMutationKey>
+      ]
+) => SWRMutationResponse<Data, Error, ExtraArg, SWRMutationKey>

package.json

@@ -31,36 +31,47 @@
       "module": "./immutable/dist/index.esm.js",
       "require": "./immutable/dist/index.js",
       "types": "./immutable/dist/immutable/index.d.ts"
+    },
+    "./mutation": {
+      "import": "./mutation/dist/index.mjs",
+      "module": "./mutation/dist/index.esm.js",
+      "require": "./mutation/dist/index.js",
+      "types": "./mutation/dist/mutation/index.d.ts"
     }
   },
   "types": "./dist/index.d.ts",
   "files": [
     "dist/**",
     "infinite/dist/**",
     "immutable/dist/**",
+    "mutation/dist/**",
     "infinite/package.json",
-    "immutable/package.json"
+    "immutable/package.json",
+    "mutation/package.json"
   ],
   "repository": "github:vercel/swr",
   "homepage": "https://swr.vercel.app",
   "license": "MIT",
   "scripts": {
-    "clean": "rimraf dist infinite/dist immutable/dist",
-    "build": "yarn build:core && yarn build:infinite && yarn build:immutable",
-    "watch": "npm-run-all -p watch:core watch:infinite watch:immutable",
+    "clean": "rimraf dist infinite/dist immutable/dist mutation/dist",
+    "build": "yarn build:core && yarn build:infinite && yarn build:immutable && yarn build:mutation",
+    "watch": "npm-run-all -p watch:core watch:infinite watch:immutable watch:mutation",
     "watch:core": "yarn build:core -w",
     "watch:infinite": "yarn build:infinite -w",
     "watch:immutable": "yarn build:immutable -w",
+    "watch:mutation": "yarn build:mutation -w",
     "build:core": "bunchee src/index.ts --no-sourcemap",
     "build:infinite": "bunchee index.ts --cwd infinite --no-sourcemap",
     "build:immutable": "bunchee index.ts --cwd immutable --no-sourcemap",
+    "build:mutation": "bunchee index.ts --cwd mutation --no-sourcemap",
     "prepublishOnly": "yarn clean && yarn build",
     "publish-beta": "yarn publish --tag beta",
     "types:check": "tsc --noEmit --project tsconfig.check.json && tsc --noEmit -p test",
     "format": "prettier --write ./**/*.{ts,tsx}",
     "lint": "eslint . --ext .ts,.tsx --cache",
     "lint:fix": "yarn lint --fix",
-    "test": "jest --coverage"
+    "coverage": "jest --coverage",
+    "test": "jest"
   },
   "husky": {
     "hooks": {

src/types.ts

@@ -145,6 +145,11 @@ export type MutatorOptions<Data = any> = {
   rollbackOnError?: boolean
 }
 
+export type MutatorConfig = {
+  revalidate?: boolean
+  populateCache?: boolean
+}
+
 export type Broadcaster<Data = any, Error = any> = (
   cache: Cache<Data>,
   key: string,

src/use-swr.ts

@@ -131,14 +131,12 @@ export const useSWRHandler = <Data = any, Error = any>(
   }
   const isValidating = resolveValidating()
 
-  const [stateRef, stateDependencies, setState] = useStateWithDeps<Data, Error>(
-    {
-      data,
-      error,
-      isValidating
-    },
-    unmountedRef
-  )
+  const currentState = {
+    data,
+    error,
+    isValidating
+  }
+  const [stateRef, stateDependencies, setState] = useStateWithDeps(currentState)
 
   // The revalidation function is a carefully crafted wrapper of the original
   // `fetcher`, to correctly handle the many edge cases.
@@ -379,10 +377,11 @@ export const useSWRHandler = <Data = any, Error = any>(
     []
   )
 
-  // Always update fetcher and config refs.
+  // Always update fetcher, config and state refs.
   useIsomorphicLayoutEffect(() => {
     fetcherRef.current = fetcher
     configRef.current = config
+    stateRef.current = currentState
   })
 
   // After mounted or key changed.

src/utils/broadcast-state.ts

@@ -1,6 +1,7 @@
 import { Broadcaster } from '../types'
 import { SWRGlobalState, GlobalState } from './global-state'
 import * as revalidateEvents from '../constants'
+import { createCacheHelper } from './cache'
 
 export const broadcastState: Broadcaster = (
   cache,
@@ -15,6 +16,8 @@ export const broadcastState: Broadcaster = (
   const revalidators = EVENT_REVALIDATORS[key]
   const updaters = STATE_UPDATERS[key]
 
+  const [get] = createCacheHelper(cache, key)
+
   // Cache was populated, update states of all hooks.
   if (broadcast && updaters) {
     for (let i = 0; i < updaters.length; ++i) {
@@ -30,10 +33,10 @@ export const broadcastState: Broadcaster = (
 
     if (revalidators && revalidators[0]) {
       return revalidators[0](revalidateEvents.MUTATE_EVENT).then(
-        () => cache.get(key).data
+        () => get().data
       )
     }
   }
 
-  return cache.get(key).data
+  return get().data
 }