当用户在MatchingPairsComponent中完成一个测试时，调用以下函数将用户的结果传输到后端。

private updateUserTestRecord = (testType) => {
const newTestRecord = {
    topicName: this.topicName,
    subtopicName:this.subtopicName,
    rightAnswers: 'n/a',
    wrongAnswers: this.wrongMatches + ' of ' + this.matchingPairsLength,
    testType,
    date: new Date(),            
}

  this.userService.updateUserTestRecord(newTestRecord)
 }

上面调用的UserService函数将用户数据传输到后端，如下所示：

public updateUserTestRecord = (newTestRecord) => {
this.httpClient
  .put<{ testRecords }>(`${this.url}/update/user/record`, newTestRecord).pipe(
    tap(testRecords => {
      console.log('testRecords',  testRecords)
      this.store.dispatch(userActions.SaveTestRecords({ testRecords }));
    }),
    catchError((errorObj) => {
      this.store.dispatch(
        messageActions.SetError({ error: errorObj.error })
      );
      throw errorObj;
    })
  ).subscribe();
 }

上述函数接收后台更新的测试记录，并更新UserReducer，UserReducer函数如下图所示：

on(userActions.SaveTestRecords, (state, action) => {
console.log('SaveTestRecords.testRecords', action.testRecords)
const currentState =  {
    ...state,
    testRecords: action.testRecords     
}

saveStateToLocalStorage(currentState);

return currentState;
 }),

问题是当UserService更新UserReducer时，数据也从TopicsReducer传输到订阅TopicsReducer的MatchingPairsComponent，即使TopicsReducer中的数据没有改变。
重复一遍，UserReducer被更新，但是数据从TopicReducer传输到MatchingPairsComponent，即使TopicReducer从未被更新。下面是MatchingPairsComponent订阅的TopicReducer函数：

export const TopicsReducers = createReducer(initialState,
on(topicsActions.StoreSubtopicData, (state, action) => { 
  console.log('Storetopics.topics', action.subtopicData)   
  return {
    ...state,
    subtopicData: action.subtopicData,
  };
}),)

下面是MatchingPairsComponent对TopicsReducer的订阅：

ngOnInit() {
   this.subscribeToReduxStores();     
 }

 private subscribeToReduxStores = () => {
window.speechSynthesis.cancel();

const topicQuestions$ = this.store.select((state) => {      
  console.log('state.topicsState', state.topicsState)

  return {
    matchingPairs: state.topicsState.matchingPairs, 
    subtopicName: state.topicsState.subtopicData.subtopicName,
    topicName: state.topicsState.subtopicData.topicName,        
  }
})

topicQuestions$.subscribe(data => {    
  console.log('topicQuestions.subscribe', data); 
  this.matchingPairs = JSON.parse(JSON.stringify(data.matchingPairs));   
  this.matchingPairsLength = this.matchingPairs.length;   
  this.topicName = data.topicName; 
  this.subtopicName = data.subtopicName;       
  this.numberOfSegments = Math.ceil(this.matchingPairs.length/this.MAXPAIRS);
  this.wrongMatches = 0;
  console.log('matchingPairs', this.matchingPairs)
  this.setupPairs(); 
})

}
TopicsReducer中的数据没有更改时，为什么TopicsReducer要将数据传输到MatchingPairsComponent，覆盖MatchingPairsComponent中当前正在处理的数据？