华建河北住房和城乡建设厅网站,专业手机建站价格,做网站创意是什么意思,哪个网站免费做简历什么是ngrx ngrx是Angular基于Rxjs的状态管理#xff0c;保存了Redux的核心概念#xff0c;并使用RxJs扩展的Redux实现。使用Observable来简化监听事件和订阅等操作。 在看这篇文章之前#xff0c;已经假设你已了解rxjs和redux。 有条件的话请查看官方文档进行学习理解。
所…什么是ngrx ngrx是Angular基于Rxjs的状态管理保存了Redux的核心概念并使用RxJs扩展的Redux实现。使用Observable来简化监听事件和订阅等操作。 在看这篇文章之前已经假设你已了解rxjs和redux。 有条件的话请查看官方文档进行学习理解。
所需包 ng add方式会自动生成所需文件并在app.module.ts中导入直接启动项目即可不报错
ng add ngrx/store
ng add ngrx/store-devtools
ng add ngrx/effects
ng add ngrx/router-storeAngular的流程
compone.ts定义变量a 改变a (没有数据请求的) this.a ; (有数据请求的) this.a this.services.search()类似的写法 用ngrx后的Angular的基本流程
写action.ts为要改变数据的操作定义不同action 写effects.ts有数据请求的通过判断action.type来发起service 写reducer.ts判断action.type返回新的store数据 component.ts从store取数据 最后告诉应用程序你写了这玩意 项目简介 本项目的两个demo都挂在example模块中
计数器-没有数据请求 app/example/container/counter.component.ts 1、先写action减和重置的action在代码里面可自行查看
// app/example/actions/counter.actions.ts
import { Action } from ngrx/store;export const INCREMENT [Counter] Increment; export class IncrementAction implements Action {readonly type INCREMENT;constructor() { }
}export type Actions IncrementAction;2、写reducer由于加不需要发送网络请求就不写effect
// app/example/reducer/counter.reducer.ts
import * as counter from ../actions/counter.actions;
// 定义接口后续counter页面如果有其他数据要保存可以在这个State里面继续添加不要忘记在initialState也要加
export interface State {counter: number;
}
// 定义初始化数据
const initialState: State {counter: 0
};
// 定义reducer 根据action type来处理状态改变对应数据
export function reducer(state initialState, action: counter.Actions): State {switch (action.type) {case counter.INCREMENT: return {counter: state.counter 1};default:return { ...state };}
}export const getCounter (state: State) state.counter;
// app/example/reducer/index.ts
import {createFeatureSelector, createSelector} from ngrx/store;// 第二步 导入我们的reducer文件
import * as fromCounter from ./counter.reducer;export interface State {counter: fromCounter.State;
}
export const reducers {counter: fromCounter.reducer
};// 将模块example的所有数据挂在store上命名为example里面保存example模块里面所有页面的数据
export const getExampleState createFeatureSelectorState(example);// 计数器页面
export const getCounterState createSelector(getExampleState, (state: State) state.counter);
export const getCounterCounter createSelector(getCounterState, fromCounter.getCounter);3、在模块中导入reduecer这样就可以运行
// app/example/example.module.tsimport {StoreModule} from ngrx/store;
import {reducers} from ./reducer;
NgModule({imports: [StoreModule.forFeature(example, reducers) // 这个才是关键哦]
})
export class ExampleModule { }
4、到这一步了我们的页面就来操作并且取数据增加啦
// src/example/container/counter.component.tsimport * as fromExample from ../../reducer;
import { Store } from ngrx/store;
import { Observable } from rxjs;
import * as counterAction from ../../actions/counter.actions;export class CounterComponent {counter$: Observablenumber;constructor(private store: StorefromExample.State) {this.counter$ store.select(fromExample.getCounterCounter);}increment() {this.store.dispatch(new counterAction.IncrementAction());}
}
页面
// app/example/container/counter.component.html
div classcontainerp classtitle计数器 没有数据请求的ngrx demo/pdiv classbtn-groupbutton nz-button nzTypeprimary (click)increment()加/buttonspan stylefont-size: 18px;font-weight: bold当前数{{counter$ | async}}/span/div
/div
npm run start看一下页面效果吧
搜索图书-有数据请求的 src/app/example/containers/book-manage/book-manage.component.ts 1、写action src/app/example/actions/book-manage.actions.ts看注释
import { Action } from ngrx/store;
import {Book} from ../model/book;
// 搜索然后搜索成功两件事情分两个action
export const SEARCH [Book Manage] Search;
export const SEARCH_COMPLETE [Book Manage] Search Complete;
// 搜索图书需要带书名称来搜索所以SearchAction有一个字符串类型的参数payload
export class SearchAction implements Action {readonly type SEARCH;constructor(public payload: string) { }
}
// 搜索出结果后图书的信息我们将其定义类型为Book结果放在数组里面所以SearchCompleteAction 的参数是Book类型数组
export class SearchCompleteAction implements Action {readonly type SEARCH_COMPLETE;constructor(public payload: Book[]) { }
}
export type Actions SearchAction| SearchCompleteAction;2、写reducersrc/app/example/reducer/book-manage.reducer.ts
import * as bookManage from ../actions/book-manage.actions;
import {Book} from ../model/book;
// book-manage页面我们暂时定义一个list变量用了存搜索图书的结果后续如果有其他变量继续在里面加
export interface State {list: Book[];
}
// 默认一开始搜索数据为空数组[]
const initialState: State {list: []
};
// 当搜索成功后更新state里面的list值
export function reducer(state initialState, action: bookManage.Actions): State {switch (action.type) {case bookManage.SEARCH_COMPLETE:return {...state,list: action.payload};default:return { ...state };}
}export const getList (state: State) state.list;
3、更新reducer src/app/example/reducer/index.ts
import {createFeatureSelector, createSelector} from ngrx/store;
import * as fromCounter from ./counter.reducer;
// 导入写好的book-manage.reducer.ts
import * as fromBookManage from ./book-manage.reducer;
export interface State {counter: fromCounter.State;bookManage: fromBookManage.State;
}
export const reducers {counter: fromCounter.reducer,bookManage: fromBookManage.reducer
};
export const getExampleState createFeatureSelectorState(example);
// 计数器
export const getCounterState createSelector(getExampleState, (state: State) state.counter);
export const getCounterCounter createSelector(getCounterState, fromCounter.getCounter);
// 图书管理
export const getBookManageState createSelector(getExampleState, (state: State) state.bookManage);
export const getBookManageList createSelector(getBookManageState, fromBookManage.getList);4、写effect检测action类型如果是search图书行为就发送网络请求查结果src/app/example/effects/book-manage.effect.ts
import {Injectable} from angular/core;
import {Actions, Effect, ofType} from ngrx/effects;
import {Observable, of} from rxjs;
import {Action} from ngrx/store;import * as bookManage from ../actions/book-manage.actions;
import {BookManageService} from ../services/book-manage.service;
import {catchError, debounceTime, map, mergeMap, skip, takeUntil} from rxjs/operators;
import {BookResult} from ../model/book;Injectable()
export class BookManageEffects {Effect()searchBook$: ObservableAction this.actions$.pipe(ofType(bookManage.SEARCH), // 判断是不是搜索图书的行为debounceTime(300), // 做延迟节省网络请求mergeMap((action: bookManage.SearchAction) {const nextSearch$ this.actions$.pipe(ofType(bookManage.SEARCH), skip(1));return this.service.searchBooks(action.payload).pipe(takeUntil(nextSearch$),// 如果搜索成功发送成功action并且带入搜索结果map((data: BookResult) ({type: bookManage.SEARCH_COMPLETE, payload: data.items})),// 如果搜索失败404之类的原因发送成功action以及空数组更新结果catchError(() of({type: bookManage.SEARCH_COMPLETE, payload: []})));}));constructor(private actions$: Actions, private service: BookManageService) {}
}5、component获取搜索结果和绑定搜索事件src/app/example/containers/book-manage/book-manage.component.ts
import { Component, OnInit } from angular/core;
import {Store} from ngrx/store;
import * as fromExample from ../../reducer;
import * as bookManageAction from ../../actions/book-manage.actions;
import {Observable} from rxjs;
import {Book} from ../../model/book;
Component({selector: app-book-manage,templateUrl: ./book-manage.component.html,styleUrls: [./book-manage.component.css]
})
export class BookManageComponent implements OnInit {searchResult$: ObservableBook[]; // 搜索到的图书列表constructor(private store: StorefromExample.State) {// 从store中选取图书搜索结果this.searchResult$ this.store.select(fromExample.getBookManageList);}ngOnInit() {}// 发送搜索行为search(bookName) {this.store.dispatch(new bookManageAction.SearchAction(bookName));}}
页面src/app/example/containers/book-manage/book-manage.component.html
div classcontainerapp-search-input (search)search($event)/app-search-inputapp-book-list [bookList]searchResult$ | async/app-book-list
/div
6、导入effect否则会不起作用哦 src/app/example/example.module.ts
...
import {BookManageEffects} from ./effects/book-manage.effect;
import {EffectsModule} from ngrx/effects;NgModule({...imports: [EffectsModule.forFeature([BookManageEffects]),],
ngrx 入门_霞霞的博客的博客-CSDN博客_ngrx文档
