feat: add selector for useAyamami hook

demo/index.tsx

@@ -8,6 +8,7 @@ import { Ayanami, Effect, EffectAction, Reducer, useAyanami } from '../src'
 
 interface State {
   count: number
+  input: string
 }
 
 interface TipsState {
@@ -30,6 +31,7 @@ class Tips extends Ayanami<TipsState> {
 class Count extends Ayanami<State> {
   defaultState = {
     count: 0,
+    input: '',
   }
 
   otherProps = ''
@@ -40,17 +42,22 @@ class Count extends Ayanami<State> {
 
   @Reducer()
   add(state: State, count: number): State {
-    return { count: state.count + count }
+    return { ...state, count: state.count + count }
   }
 
   @Reducer()
   addOne(state: State): State {
-    return { count: state.count + 1 }
+    return { ...state, count: state.count + 1 }
   }
 
   @Reducer()
   reset(): State {
-    return { count: 0 }
+    return { count: 0, input: '' }
+  }
+
+  @Reducer()
+  changeInput(state: State, value: string): State {
+    return { ...state, input: value }
   }
 
   @Effect()
@@ -67,7 +74,7 @@ class Count extends Ayanami<State> {
 }
 
 function CountComponent() {
-  const [{ count }, actions] = useAyanami(Count)
+  const [{ count, input }, actions] = useAyanami(Count)
   const [{ tips }] = useAyanami(Tips)
 
   const add = (count: number) => () => actions.add(count)
@@ -76,12 +83,26 @@ function CountComponent() {
   return (
     <div>
       <p>count: {count}</p>
+      <p>input: {input}</p>
       <p>tips: {tips}</p>
       <button onClick={add(1)}>add one</button>
       <button onClick={minus(1)}>minus one</button>
-      <button onClick={actions.reset}>reset to zero</button>
+      <button onClick={actions.reset}>reset</button>
+      <InputComponent />
     </div>
   )
 }
 
+const InputComponent = React.memo(() => {
+  const [input, actions] = useAyanami(Count, { selector: (state) => state.input })
+
+  return (
+    <div>
+      <h3>{input}</h3>
+      <input value={input} onChange={(e) => actions.changeInput(e.target.value)} />
+    </div>
+  )
+})
+InputComponent.displayName = 'InputComponent'
+
 ReactDOM.render(<CountComponent />, document.querySelector('#app'))

src/hooks/shallow-equal.ts

@@ -0,0 +1,10 @@
+export const shallowEqual = (a: any, b: any): boolean => {
+  if (a === b) return true
+  if (typeof a === 'object' && typeof b === 'object' && a !== null && b !== null) {
+    return (
+      Object.keys(a).length === Object.keys(b).length &&
+      Object.keys(a).every((key) => a[key] === b[key])
+    )
+  }
+  return false
+}

src/hooks/use-ayanami-instance.ts

@@ -4,25 +4,19 @@ import get from 'lodash/get'
 import { ActionMethodOfAyanami, Ayanami, combineWithIkari } from '../core'
 import { useSubscribeAyanamiState } from './use-subscribe-ayanami-state'
 
-export interface UseAyanamiInstanceConfig {
+export interface UseAyanamiInstanceConfig<S, U> {
   destroyWhenUnmount?: boolean
+  selector?: (state: S) => U
 }
 
-export type UseAyanamiInstanceResult<M extends Ayanami<S>, S> = [
-  Readonly<S>,
-  ActionMethodOfAyanami<M, S>,
-]
+export type UseAyanamiInstanceResult<M extends Ayanami<S>, S, U> = [U, ActionMethodOfAyanami<M, S>]
 
-type Config = UseAyanamiInstanceConfig
-
-type Result<M extends Ayanami<S>, S> = UseAyanamiInstanceResult<M, S>
-
-export function useAyanamiInstance<M extends Ayanami<S>, S>(
+export function useAyanamiInstance<M extends Ayanami<S>, S, U>(
   ayanami: M,
-  config?: Config,
-): Result<M, S> {
+  config?: UseAyanamiInstanceConfig<S, U>,
+): UseAyanamiInstanceResult<M, S, U> {
   const ikari = React.useMemo(() => combineWithIkari(ayanami), [ayanami])
-  const state = useSubscribeAyanamiState(ayanami)
+  const state = useSubscribeAyanamiState(ayanami, config ? config.selector : undefined)
 
   React.useEffect(
     () => () => {
@@ -35,5 +29,5 @@ export function useAyanamiInstance<M extends Ayanami<S>, S>(
     [ayanami, config],
   )
 
-  return [state, ikari.triggerActions] as Result<M, S>
+  return [state, ikari.triggerActions] as UseAyanamiInstanceResult<M, S, U>
 }

src/hooks/use-ayanami.ts

@@ -15,23 +15,28 @@ import { SSRContext } from '../ssr/ssr-context'
 
 import {
   useAyanamiInstance,
-  UseAyanamiInstanceResult,
+  UseAyanamiInstanceResult as Result,
   UseAyanamiInstanceConfig,
 } from './use-ayanami-instance'
 
-export function useAyanami<M extends Ayanami<S>, S>(
+interface Config<S, U> extends Partial<ScopeConfig> {
+  selector?: (state: S) => U
+}
+
+export function useAyanami<M extends Ayanami<S>, S, U = M extends Ayanami<infer SS> ? SS : S>(
   A: ConstructorOf<M>,
-  config?: ScopeConfig,
-): M extends Ayanami<infer SS> ? UseAyanamiInstanceResult<M, SS> : UseAyanamiInstanceResult<M, S> {
+  config?: M extends Ayanami<infer SS> ? Config<SS, U> : Config<S, U>,
+): M extends Ayanami<infer SS> ? Result<M, SS, U> : Result<M, S, U> {
   const scope = get(config, 'scope')
+  const selector = get(config, 'selector')
   const req = isSSREnabled() ? React.useContext(SSRContext) : null
   const reqScope = req ? createScopeWithRequest(req, scope) : scope
   const ayanami = React.useMemo(() => getInstanceWithScope(A, reqScope), [reqScope])
   ayanami.scopeName = scope || DEFAULT_SCOPE_NAME
 
-  const useAyanamiInstanceConfig = React.useMemo((): UseAyanamiInstanceConfig => {
-    return { destroyWhenUnmount: scope === TransientScope }
+  const useAyanamiInstanceConfig = React.useMemo((): UseAyanamiInstanceConfig<S, U> => {
+    return { destroyWhenUnmount: scope === TransientScope, selector }
   }, [reqScope])
 
-  return useAyanamiInstance<M, S>(ayanami, useAyanamiInstanceConfig) as any
+  return useAyanamiInstance<M, S, U>(ayanami, useAyanamiInstanceConfig) as any
 }

src/hooks/use-subscribe-ayanami-state.ts

@@ -1,13 +1,20 @@
 import * as React from 'react'
 import { Subscription } from 'rxjs'
-
+import identity from 'lodash/identity'
+import { shallowEqual } from './shallow-equal'
 import { Ayanami } from '../core'
 
-export function useSubscribeAyanamiState<M extends Ayanami<S>, S>(ayanami: M): S {
+export function useSubscribeAyanamiState<M extends Ayanami<S>, S, U>(
+  ayanami: M,
+  selector: (state: S) => U = identity,
+): unknown {
+  const state = ayanami.getState()
+
   const ayanamiRef = React.useRef<Ayanami<S> | null>(null)
   const subscriptionRef = React.useRef<Subscription | null>(null)
+  const stateRef = React.useRef<S>(state)
 
-  const [state, setState] = React.useState<S>(() => ayanami.getState())
+  const [, forceUpdate] = React.useState({})
 
   if (ayanamiRef.current !== ayanami) {
     ayanamiRef.current = ayanami
@@ -18,7 +25,12 @@ export function useSubscribeAyanamiState<M extends Ayanami<S>, S>(ayanami: M): S
     }
 
     if (ayanami) {
-      subscriptionRef.current = ayanami.getState$().subscribe(setState)
+      subscriptionRef.current = ayanami.getState$().subscribe((state) => {
+        const before = selector(stateRef.current)
+        const after = selector(state)
+        if (!shallowEqual(before, after)) forceUpdate({})
+        stateRef.current = state
+      })
     }
   }
 
@@ -31,5 +43,5 @@ export function useSubscribeAyanamiState<M extends Ayanami<S>, S>(ayanami: M): S
     [subscriptionRef],
   )
 
-  return state
+  return selector(state)
 }

test/specs/hooks.spec.tsx

@@ -9,6 +9,7 @@ import { useCallback, useEffect } from 'react'
 
 interface State {
   count: number
+  anotherCount: number
 }
 
 enum CountAction {
@@ -27,6 +28,7 @@ const numberProvider: ValueProvider = {
 class Count extends Ayanami<State> {
   defaultState = {
     count: -1,
+    anotherCount: 0,
   }
 
   constructor(@Inject(numberProvider.provide) number: number) {
@@ -98,6 +100,33 @@ describe('Hooks spec:', () => {
       expect(count()).toBe('0')
     })
 
+    it('State selector work properly', () => {
+      const innerRenderSpy = jest.fn()
+      const outerRenderSpy = jest.fn()
+
+      const InnerComponent = React.memo(({ scope }: { scope?: any }) => {
+        const [anotherCount] = useAyanami(Count, { selector: (state) => state.anotherCount, scope })
+        innerRenderSpy(anotherCount)
+        return <div />
+      })
+
+      const OuterComponent = () => {
+        const [state, actions] = useAyanami(Count, { scope: TransientScope })
+        const addOne = useCallback(() => actions.add(1), [])
+        outerRenderSpy(state.count)
+        return (
+          <div>
+            <button onClick={addOne}>add one</button>
+            <InnerComponent />
+          </div>
+        )
+      }
+      const renderer = create(<OuterComponent />)
+      act(() => renderer.root.findByType('button').props.onClick())
+      expect(innerRenderSpy.mock.calls).toEqual([[0]])
+      expect(outerRenderSpy.mock.calls).toEqual([[0], [1]])
+    })
+
     it('should only render once when update the state right during rendering', () => {
       const spy = jest.fn()
       const TestComponent = () => {