NgRx 状态添加/更新为数组并保持同步

Question

如果需要添加多个对象，如何使用 ngrx 更新状态？

例如，在下面的示例中，一个用户可以与多个任务相关联。

目前，当所有任务都返回时，存储会更新两次，每次更新时，最后一个任务都会被一个新任务替换。这是预期的行为，但您将如何初始化一个数组并捕获更新以作为对象数组的状态并确保它保持同步？

task.reducer.ts

import * as TaskActions from './task.actions';
import { Action, createReducer, on } from '@ngrx/store';
import { ITask } from '../../models/task';

export interface State {
  task: ITask | null;
  error: any;
}

const initialState: ITask = {
  basketTotal: 0,
  carePlanPrice: 0,
  category: null,
  completionDate: null
};

export const taskReducer = createReducer(
  initialState,
  on(TaskActions.getData, state => ({ ...state })),
  on(TaskActions.dataReceived, (state, payload) => ({ ...state, payload })),
  on(TaskActions.dataNotReceived, state => ({ ...state })),
  on(TaskActions.signOut, state => ({ ...state })),
  on(TaskActions.signOutSuccess, state => ({ ...state, ...initialState })),
);

export function reducer(state: ITask | undefined, action: Action) {
  return taskReducer(state, action);
}

task.effect.ts

  @Effect()
  getData$ = this.actions$.pipe(
    ofType(TaskActions.getData),
    switchMap(() => {
      return this.afs.collection<ITask>('tasks', ref =>
        ref.where('createdBy', '==', localStorage.getItem('uid'))).stateChanges().pipe(
      );
    }),
    mergeMap(actions => actions),
    map(action => {
      if (action.payload) {
        return TaskActions.dataReceived({ payload: TaskService.parseData(action.payload.doc.data()) });
      } else {
        return TaskActions.dataNotReceived();
      }
    })
  );

task.actions.ts

import { createAction, props } from '@ngrx/store';
import { ITask } from '../../models/task';

export const getData = createAction('[Task] Get Data');
export const dataReceived = createAction('[Task] Data Received', props<{ payload: Partial<ITask> }>());
export const dataNotReceived = createAction('[Task] Data Not Received');
export const signOut = createAction('[Task] Sign Out');
export const signOutSuccess = createAction('[Task] Sign Out Success');

更新：

我试过了

on(TaskActions.dataReceived, (state, payload) => 
  ({ 
      ...state, 
      tasks: [...state.tasks,  payload.payload ] 
  })),

结果如下：

我期待一个包含两个项目的数组：

task: [
  { ... }, { ... }
]

Answer 1

spread语法也可以用于数组创建一个克隆。

on(TaskActions.dataReceived, (state, payload) => 
  ({ 
      ...state, 
      tasks: payload.condition ? [...state.tasks,  payload.newTask ] : []
  })),

见Spread syntax docs