Merge pull request #2091 from aryaemami59/identity-function

docs/api/hooks.md

@@ -48,12 +48,14 @@ From there, you may import any of the listed React Redux hooks APIs and use them
 type RootState = ReturnType<typeof store.getState>
 type SelectorFn = <Selected>(state: RootState) => Selected
 type EqualityFn = (a: any, b: any) => boolean
-export type CheckFrequency = 'never' | 'once' | 'always'
+export type DevModeCheckFrequency = 'never' | 'once' | 'always'
 
 interface UseSelectorOptions {
   equalityFn?: EqualityFn
-  stabilityCheck?: CheckFrequency
-  noopCheck?: CheckFrequency
+  devModeChecks?: {
+    stabilityCheck?: DevModeCheckFrequency
+    identityFunctionCheck?: DevModeCheckFrequency
+  }
 }
 
 const result: Selected = useSelector(
@@ -296,14 +298,24 @@ By default, this will only happen when the selector is first called. You can con
 
 ```tsx title="Individual hook setting"
 function Component() {
-  const count = useSelector(selectCount, { stabilityCheck: 'never' })
+  const count = useSelector(selectCount, {
+    devModeChecks: { stabilityCheck: 'never' },
+  })
   // run once (default)
-  const user = useSelector(selectUser, { stabilityCheck: 'once' })
+  const user = useSelector(selectUser, {
+    devModeChecks: { stabilityCheck: 'once' },
+  })
   // ...
 }
 ```
 
-#### No-op selector check
+#### Identity Function (`state => state`) Check
+
+:::danger Breaking Change!
+
+This was previously referred to as `noopCheck`.
+
+:::
 
 In development, a check is conducted on the result returned by the selector. It warns in the console if the result is the same as the parameter passed in, i.e. the root state.
 
@@ -321,16 +333,20 @@ const user = useSelector((state) => state.auth.currentUser)
 By default, this will only happen when the selector is first called. You can configure the check in the Provider or at each `useSelector` call.
 
 ```tsx title="Global setting via context"
-<Provider store={store} noopCheck="always">
+<Provider store={store} identityFunctionCheck="always">
   {children}
 </Provider>
 ```
 
 ```tsx title="Individual hook setting"
 function Component() {
-  const count = useSelector(selectCount, { noopCheck: 'never' })
+  const count = useSelector(selectCount, {
+    devModeChecks: { identityFunctionCheck: 'never' },
+  })
   // run once (default)
-  const user = useSelector(selectUser, { noopCheck: 'once' })
+  const user = useSelector(selectUser, {
+    devModeChecks: { identityFunctionCheck: 'once' },
+  })
   // ...
 }
 ```

docs/using-react-redux/connect-extracting-data-with-mapStateToProps.md

@@ -69,7 +69,7 @@ function mapStateToProps(state, ownProps) {
 }
 
 // Later, in your application, a parent component renders:
-;<ConnectedTodo id={123} />
+<ConnectedTodo id={123} />
 // and your component receives props.id, props.todo, and props.visibilityFilter
 ```
 

src/components/Context.ts

@@ -1,18 +1,16 @@
-import * as React from 'react'
 import type { Context } from 'react'
+import * as React from 'react'
 import type { Action, Store, UnknownAction } from 'redux'
 import type { Subscription } from '../utils/Subscription'
-import type { CheckFrequency } from '../hooks/useSelector'
+import type { ProviderProps } from './Provider'
 
 export interface ReactReduxContextValue<
   SS = any,
   A extends Action<string> = UnknownAction
-> {
+> extends Pick<ProviderProps, 'stabilityCheck' | 'identityFunctionCheck'> {
   store: Store<SS, A>
   subscription: Subscription
   getServerState?: () => SS
-  stabilityCheck: CheckFrequency
-  noopCheck: CheckFrequency
 }
 
 const ContextKey = Symbol.for(`react-redux-context`)

src/components/Provider.tsx

@@ -1,11 +1,11 @@
 import type { Context, ReactNode } from 'react'
 import * as React from 'react'
-import type { ReactReduxContextValue } from './Context'
-import { ReactReduxContext } from './Context'
+import type { Action, Store, UnknownAction } from 'redux'
+import type { DevModeCheckFrequency } from '../hooks/useSelector'
 import { createSubscription } from '../utils/Subscription'
 import { useIsomorphicLayoutEffect } from '../utils/useIsomorphicLayoutEffect'
-import type { Action, Store, UnknownAction } from 'redux'
-import type { CheckFrequency } from '../hooks/useSelector'
+import type { ReactReduxContextValue } from './Context'
+import { ReactReduxContext } from './Context'
 
 export interface ProviderProps<
   A extends Action<string> = UnknownAction,
@@ -29,11 +29,27 @@ export interface ProviderProps<
    */
   context?: Context<ReactReduxContextValue<S, A> | null>
 
-  /** Global configuration for the `useSelector` stability check */
-  stabilityCheck?: CheckFrequency
+  /**
+   * Determines the frequency of stability checks for all selectors.
+   * This setting overrides the global configuration for
+   * the `useSelector` stability check, allowing you to specify how often
+   * these checks should occur in development mode.
+   *
+   * @since 8.1.0
+   */
+  stabilityCheck?: DevModeCheckFrequency
 
-  /** Global configuration for the `useSelector` no-op check */
-  noopCheck?: CheckFrequency
+  /**
+   * Determines the frequency of identity function checks for all selectors.
+   * This setting overrides the global configuration for
+   * the `useSelector` identity function check, allowing you to specify how often
+   * these checks should occur in development mode.
+   *
+   * **Note**: Previously referred to as `noopCheck`.
+   *
+   * @since 9.0.0
+   */
+  identityFunctionCheck?: DevModeCheckFrequency
 
   children: ReactNode
 }
@@ -44,7 +60,7 @@ function Provider<A extends Action<string> = UnknownAction, S = unknown>({
   children,
   serverState,
   stabilityCheck = 'once',
-  noopCheck = 'once',
+  identityFunctionCheck = 'once',
 }: ProviderProps<A, S>) {
   const contextValue = React.useMemo(() => {
     const subscription = createSubscription(store)
@@ -53,9 +69,9 @@ function Provider<A extends Action<string> = UnknownAction, S = unknown>({
       subscription,
       getServerState: serverState ? () => serverState : undefined,
       stabilityCheck,
-      noopCheck,
+      identityFunctionCheck,
     }
-  }, [store, serverState, stabilityCheck, noopCheck])
+  }, [store, serverState, stabilityCheck, identityFunctionCheck])
 
   const previousState = React.useMemo(() => store.getState(), [store])
 

src/hooks/useSelector.ts

@@ -1,21 +1,68 @@
 import * as React from 'react'
 
-import {
-  createReduxContextHook,
-  useReduxContext as useDefaultReduxContext,
-} from './useReduxContext'
 import type { ReactReduxContextValue } from '../components/Context'
 import { ReactReduxContext } from '../components/Context'
 import type { EqualityFn, NoInfer } from '../types'
 import type { uSESWS } from '../utils/useSyncExternalStore'
 import { notInitialized } from '../utils/useSyncExternalStore'
+import {
+  createReduxContextHook,
+  useReduxContext as useDefaultReduxContext,
+} from './useReduxContext'
+
+/**
+ * The frequency of development mode checks.
+ *
+ * @since 8.1.0
+ * @internal
+ */
+export type DevModeCheckFrequency = 'never' | 'once' | 'always'
+
+/**
+ * Represents the configuration for development mode checks.
+ *
+ * @since 9.0.0
+ * @internal
+ */
+export interface DevModeChecks {
+  /**
+   * Overrides the global stability check for the selector.
+   * - `once` - Run only the first time the selector is called.
+   * - `always` - Run every time the selector is called.
+   * - `never` - Never run the stability check.
+   *
+   * @default 'once'
+   *
+   * @since 8.1.0
+   */
+  stabilityCheck: DevModeCheckFrequency
 
-export type CheckFrequency = 'never' | 'once' | 'always'
+  /**
+   * Overrides the global identity function check for the selector.
+   * - `once` - Run only the first time the selector is called.
+   * - `always` - Run every time the selector is called.
+   * - `never` - Never run the identity function check.
+   *
+   * **Note**: Previously referred to as `noopCheck`.
+   *
+   * @default 'once'
+   *
+   * @since 9.0.0
+   */
+  identityFunctionCheck: DevModeCheckFrequency
+}
 
 export interface UseSelectorOptions<Selected = unknown> {
   equalityFn?: EqualityFn<Selected>
-  stabilityCheck?: CheckFrequency
-  noopCheck?: CheckFrequency
+
+  /**
+   * `useSelector` performs additional checks in development mode to help
+   * identify and warn about potential issues in selector behavior. This
+   * option allows you to customize the behavior of these checks per selector.
+   *
+   * @since 9.0.0
+   */
+  devModeChecks?: Partial<DevModeChecks>
 }
 
 export interface UseSelector {
@@ -59,13 +106,10 @@ export function createSelectorHook(
       | EqualityFn<NoInfer<Selected>>
       | UseSelectorOptions<NoInfer<Selected>> = {}
   ): Selected {
-    const {
-      equalityFn = refEquality,
-      stabilityCheck = undefined,
-      noopCheck = undefined,
-    } = typeof equalityFnOrOptions === 'function'
-      ? { equalityFn: equalityFnOrOptions }
-      : equalityFnOrOptions
+    const { equalityFn = refEquality, devModeChecks = {} } =
+      typeof equalityFnOrOptions === 'function'
+        ? { equalityFn: equalityFnOrOptions }
+        : equalityFnOrOptions
     if (process.env.NODE_ENV !== 'production') {
       if (!selector) {
         throw new Error(`You must pass a selector to useSelector`)
@@ -84,8 +128,8 @@ export function createSelectorHook(
       store,
       subscription,
       getServerState,
-      stabilityCheck: globalStabilityCheck,
-      noopCheck: globalNoopCheck,
+      stabilityCheck,
+      identityFunctionCheck,
     } = useReduxContext()
 
     const firstRun = React.useRef(true)
@@ -95,10 +139,14 @@ export function createSelectorHook(
         [selector.name](state: TState) {
           const selected = selector(state)
           if (process.env.NODE_ENV !== 'production') {
-            const finalStabilityCheck =
-              typeof stabilityCheck === 'undefined'
-                ? globalStabilityCheck
-                : stabilityCheck
+            const {
+              identityFunctionCheck: finalIdentityFunctionCheck,
+              stabilityCheck: finalStabilityCheck,
+            } = {
+              stabilityCheck,
+              identityFunctionCheck,
+              ...devModeChecks,
+            }
             if (
               finalStabilityCheck === 'always' ||
               (finalStabilityCheck === 'once' && firstRun.current)
@@ -125,11 +173,9 @@ export function createSelectorHook(
                 )
               }
             }
-            const finalNoopCheck =
-              typeof noopCheck === 'undefined' ? globalNoopCheck : noopCheck
             if (
-              finalNoopCheck === 'always' ||
-              (finalNoopCheck === 'once' && firstRun.current)
+              finalIdentityFunctionCheck === 'always' ||
+              (finalIdentityFunctionCheck === 'once' && firstRun.current)
             ) {
               // @ts-ignore
               if (selected === state) {
@@ -153,7 +199,7 @@ export function createSelectorHook(
           return selected
         },
       }[selector.name],
-      [selector, globalStabilityCheck, stabilityCheck]
+      [selector, stabilityCheck, devModeChecks.stabilityCheck]
     )
 
     const selectedState = useSyncExternalStoreWithSelector(