Observable Service - 误解/最佳实践

Question

我正在努力解决两个组件之间的观察服务方法。我有一个包含设置组件的配置文件组件。两者都使用 user.service，其中提供程序在 app.module.ts 中定义。提供者未在其他任何地方定义。因此，当我将 settings.component 上的 firstName 更改为示例并保存时。在我重新加载页面之前，更改不会反映在 profile.component 侧边栏中。

下班后： 我找到了一个解决方案，通过一个事件发射器来做到这一点，该事件发射器将在更新发生时立即触发。这将解决我上面的问题，但我认为这不是正确的方法，因为我阅读了下面的文章：

没有事件发射器它不应该工作吗？

所以我的问题是： 对于这种情况，您会使用什么方法或最佳做法是什么？当然，我的代码中可能存在问题。我真的是 angular 的新手。

app.module.ts

在 app.module.ts 中我定义了：

 providers: [UserService]

profile.component.ts

@Component({
    selector: 'app-profile',
    templateUrl: './profile.component.html',
    styleUrls: ['./profile.component.css']
})

export class ProfileComponent implements OnInit {
    user: any;
    Role = Role;
    constructor(private _userService: UserService, ) { }


    ngOnInit() {
        const token = localStorage.getItem('token');
        const role = jwt.decode(token).user.role;
        this._userService.getUser().subscribe(v => { this.user = v; });
        // Event Emmiter Subscription
        this._userService.change.subscribe(v => { this.user = v; });
    }
}

profile.component.html

<div *ngIf="user" class="container mt50">
    <div class="row profile">
        <div class="col-md-3">
            <div class="profile-sidebar">
                <!-- SIDEBAR USERPIC -->
                <div class="profile-userpic">
                    <img gravatar [email]="user.email" [size]="256" class="img-responsive animated bounceIn" alt="">
                </div>
                <!-- END SIDEBAR USERPIC -->
                <!-- SIDEBAR USER TITLE -->
                <div class="profile-usertitle">
                    <div class="profile-usertitle-name">
                        {{ user.firstName }} {{ user.lastName }}
                    </div>
                    <div class="profile-usertitle-job">
                        {{ user.email }}
                    </div>
                </div>
            </div>
        </div>
        <div class="col-md-9">
                <app-profile-settings-admin *ngIf="user.role === Role.ADMINISTRATOR"></app-profile-settings-admin>
        </div>
    </div>
</div>

user.service.ts

@Injectable()
export class UserService {
    public user: any;

    constructor(private http: Http) { }
    // EVENT EMIITER
    public change: EventEmitter<any> = new EventEmitter();
    getUser() {
        const token = localStorage.getItem('token')
            ? '?token=' + localStorage.getItem('token')
            : '';
        return this.http.get('api/user' + token)
            .map((response: Response) => {
                this.user = response.json().obj;
                return this.user;
            })
            .catch((error: Response) => Observable.throw(error.json()));
    }

    updateUser(user) {
        const body = JSON.stringify(user);
        const headers = new Headers({'Content-Type': 'application/json'});
        const token = localStorage.getItem('token')
            ? '?token=' + localStorage.getItem('token')
            : '';
        return this.http.patch('api/user/' + token, body, {headers: headers})
            .map((response: Response) => {
                const result = response.json();
                this.user = result.obj;
                // EMIT EVENT
                this.change.emit(this.user);
                return this.user;
            })
            .catch((error: Response) => Observable.throw(error.json()));
    }
}

profile.settings.admin.component.ts

在该组件中，只有一个表单会在提交时触发以下代码：

onSubmit() {
    this._userService.updateUser(this.userForm.value)
        .subscribe(
            data => {
                this._toastyService.default('Settings saved!');
                console.log(data);
            },
            error =>{
                this._toastyService.default('Error occured!');
                console.log(error);
            }
        );
}

Answer 1

Live working example 您无需触发事件即可在组件之间共享（和同步）数据。让 Angular 服务（和 Angular 表单）为您控制：

Profile.component

ngOnInit() {
    const token = localStorage.getItem('token');
    const role = jwt.decodeToken(token).user.role;
    this._userService.getUser().subscribe(v => {
        this.user = v; 
    });
}

user.service

getUser() {
    const token = localStorage.getItem('token')
        ? '?token=' + localStorage.getItem('token')
        : '';
    return this.http.get('api/user' + token)
        .pipe(map((user: HttpResponse<any>) => {
            this.user = user;
                return this.user;
            }),
        catchError((error: HttpErrorResponse) => Observable.throw(error)))
}

updateUser(user) {
    const body = JSON.stringify(user);
    const headers: HttpHeaders =  new HttpHeaders({'Content-Type': 'application/json'});
    const token = localStorage.getItem('token')
        ? '?token=' + localStorage.getItem('token')
        : '';
    return this.http.patch('api/user/' + token, body, {headers})
        .pipe(map((user: HttpResponse<any>) => {
            this.user = user;
            return this.user;
        }),
        catchError((error: HttpErrorResponse) => Observable.throw(error)));
}

profile.settings.admin.component.ts

ngOnInit() {
    this._userService.getUser().subscribe((user: User) => {
        this.user = user;         
    });
}

onSubmit() {
    this._userService.updateUser(this.user)
        .subscribe(
            data => {
                this._toastyService.default('Settings saved!');
                console.log(data);
            },
            error =>{
                this._toastyService.default('Error occured!');
                console.log(error);
            }
        );
}

profile.settings.admin.component.html

<form #userForm="ngForm">
    <div class="form-group">
        <label for="name">Name</label>
        <input type="text" class="form-control" id="name" aria-describedby="nameHelp" 
            placeholder="enter name" [(ngModel)]="user.name" name="name" required #name="ngModel">
        <div [hidden]="name.valid || name.pristine"
            class="alert alert-danger">
            Name is required
        </div>
    </div>
     <div class="form-group">
        <label for="lastName">Last Name</label>
        <input type="text" class="form-control" id="lastName" aria-describedby="lastNameHelp" 
            placeholder="enter last name" [(ngModel)]="user.lastName" name="lastName" required #lastName="ngModel">
        <div [hidden]="lastName.valid || lastName.pristine"
            class="alert alert-danger">
            last Name is required
        </div>
    </div>
    <div class="form-group">
        <label for="email">Email</label>
        <input type="email" class="form-control" id="email" aria-describedby="emailHelp" 
            placeholder="enter email" [(ngModel)]="user.email" name="email" required #email="ngModel">
        <div [hidden]="email.valid || email.pristine"
            class="alert alert-danger">
            email is required
        </div>
    </div>

    <button type="submit" class="btn btn-success" (click)="onSubmit()" >Submit</button>
</form>

Observable Service - 误解/最佳实践

Obseravables Service - Missunderstanding / Best Practise

observable

angular

angular-event-emitter