尊敬的Stackoverflow社区。 p>
我是NgRx的新手,正试图找出它是如何工作的。我创建了一个应用-基于Angular 6,Firebase和NgRx的简单商店清单。
我在集合中添加了两个名为Product
的项目,并尝试通过ngrx模式获取它们。似乎我做得很好-我已经在GET_PRODUCTS_SUCCESS
中将项目作为有效负载获取,但是我无法将它们放入视图中显示,产品未定义。我尝试通过两种方式进行操作:
this.store.select(getProducts).subscribe(products => {
console.log('products', products); // undefined
});
和
this.products = this.store.select(getProducts); // Store
第二种方式,我得到了整个商店... 下面的代码。
product.actions.ts
import { Action } from '@ngrx/store';
import { Product } from '../../models/product.model';
export const GET_PRODUCTS = 'Get_products';
export const GET_PRODUCTS_SUCCESS = 'Get_products_success';
export class GetProducts implements Action {
readonly type = GET_PRODUCTS;
constructor(public payload = '') {}
}
export class GetProductsSuccess implements Action {
readonly type = GET_PRODUCTS_SUCCESS;
constructor(public payload?: Product[]) {}
}
export type Actions = GetProducts | GetProductsSuccess;
product.reducer.ts
import { Product } from '../../models/product.model';
import * as productAction from './products.action';
export interface State {
products: Product[];
loading: boolean;
}
export const initialState: State = {
products: [],
loading: false,
};
export function ProductsReducer(state: State = initialState, action: productAction.Actions) {
switch (action.type) {
case productAction.GET_PRODUCTS:
return {...state, loading: true};
case productAction.GET_PRODUCTS_SUCCESS:
const test = {...state, products: action.payload, loading: false};
console.log("test", test);
return test;
default:
return state;
}
}
product.effects.ts
import { Injectable } from '@angular/core';
import { Action } from '@ngrx/store';
import { Effect, Actions } from '@ngrx/effects';
import { AngularFirestore } from '@angular/fire/firestore';
import { Product } from '../../models/product.model';
import * as productAction from './products.action';
import { Observable, of } from 'rxjs';
import { switchMap, map, mergeMap } from 'rxjs/operators';
@Injectable()
export class ProductEffects {
constructor(private actions$: Actions, private db: AngularFirestore) {}
@Effect()
getProducts: Observable<Action> = this.actions$
.ofType(productAction.GET_PRODUCTS).pipe(
switchMap(() => {
return this.db.collection<Product>('products').valueChanges()
.pipe(
map((payload) => {
return {
type: 'Get_products_success',
payload: payload
};
})
);
})
);
}
product.selector.ts
import { createSelector } from '@ngrx/store';
import { State } from './products.reducer';
import { Product } from '../../models/product.model';
export function getState(state: State): State {
return state;
}
export function fetchProducts(state: State): Product[] {
return state.products;
}
export const getProducts = createSelector(getState, fetchProducts);
list.component.ts-获取并显示所有产品
import { Component, OnInit } from '@angular/core';
import { Store } from '@ngrx/store';
import { Product } from '../../models/product.model';
import * as productActions from '../../store/products/products.action';
import { State } from '../../store/products/products.reducer';
import { getProducts } from '../../store/products/products.selector';
import { Observable } from 'rxjs';
@Component({
selector: 'app-list',
templateUrl: './list.component.html',
styleUrls: ['./list.component.scss']
})
export class ListComponent implements OnInit {
products: Observable<Product[]>;
constructor(private store: Store<State>) {}
ngOnInit() {
this.store.dispatch(new productActions.GetProducts);
this.store.select(getProducts).subscribe(products => {
console.log('products', products);
});
}
}
如果您发现我做错了-不要害羞告诉我。 我真的需要你的帮助。谢谢。
答案 0 :(得分:3)
好吧,我发现了...
我看着我还能如何从存储请求数据。我找到了一种方法,在我的应用中,它看起来像
this.store.select(state => state).subscribe(data => {
console.log('data', data);
});
然后我进入控制台对象:
{ message: { Products: Array[3], loading: false } }
WTF?什么消息?我进行了全局搜索,发现我在app.module.ts
中实现了我的reducer:
StoreModule.forRoot({ message: ProductReducer }),
好的。因此,我在reducers文件夹中创建了index.ts
并导出了以下的reducer:
import { ActionReducerMap } from '@ngrx/store';
import * as fromProducts from './products.reducer';
export interface AppState {
products: fromProducts.ProductState;
}
export const reducers: ActionReducerMap<AppState> = {
products: fromProducts.productsReducer
};
现在在app.module.ts
中,它导入为
StoreModule.forRoot(reducers),
现在此代码运行良好:
this.store.select(getProducts).subscribe(products => {
console.log('products', products);
});