observable

问题 I need a with RxJS for MySQL in NodeJS. Could someone give me an example for one select? On front-end I will use Angular2. 回答1: In my case, I'm using the MySQL npm package in a desktop application made with Electron and Angular. However the same should work even on a plain NodeJS application by installing and importing rxjs. I've first installed mysql and @types/mysql package with: npm install --saved-dev mysql @types/mysql Then I've created a MySQL service: import { Injectable } from '

问题 I have a content view where i'm showing a list of items using ForEach @ObservedObject var homeVM : HomeViewModel var body: some View { ScrollView (.horizontal, showsIndicators: false) { HStack(spacing: 10) { Spacer().frame(width:8) ForEach(homeVM.favoriteStores , id: \._id){ item in StoreRowOneView(storeVM: item) } Spacer().frame(width:8) } }.frame(height: 100) } And my ObservableObject contains @Published var favoriteStores = [StoreViewModel]() And StoreViewModel is defined as below class

问题 I want to be able to cache an http call, but also force the cache to refresh. My service looks like this: @Injectable() export class UserService { private currentUser$: Observable<User>; constructor(private http: HttpClient) { } getCurrentUser(force = false): Observable<User> { if (!this.currentUser$ || force) { this.currentUser$ = this.http.get<User>(`${environment.API_URL}/profiles/me`) .pipe( shareReplay(CACHE_SIZE) ); } return this.currentUser$; } } If I call getCurrentUser(true) , the

问题 For a JWT authentification, I make a post request to get the token using the new Http module working with Observables now. I have a simple Login component showing the form: @Component({ selector: 'my-login', template: `<form (submit)="submitForm($event)"> <input [(ngModel)]="cred.username" type="text" required autofocus> <input [(ngModel)]="cred.password" type="password" required> <button type="submit">Connexion</button> </form>` }) export class LoginComponent { private cred: CredentialsModel

问题 For a JWT authentification, I make a post request to get the token using the new Http module working with Observables now. I have a simple Login component showing the form: @Component({ selector: 'my-login', template: `<form (submit)="submitForm($event)"> <input [(ngModel)]="cred.username" type="text" required autofocus> <input [(ngModel)]="cred.password" type="password" required> <button type="submit">Connexion</button> </form>` }) export class LoginComponent { private cred: CredentialsModel

问题 With RxJS Observables within Angular this.myService.getEmp(personEmpId).subscribe( result => { this.personName = result.person_name; }, error => { console.log("EE:",error); } ); How can I test if my subscription to this service returns a NULL result, i.e. no record was found at all? I tried adding the error part but this did not fire the console message. At the moment, I seem to be getting the following error message: ERROR TypeError: "result is null" 回答1: You can add a filter before

问题 With RxJS Observables within Angular this.myService.getEmp(personEmpId).subscribe( result => { this.personName = result.person_name; }, error => { console.log("EE:",error); } ); How can I test if my subscription to this service returns a NULL result, i.e. no record was found at all? I tried adding the error part but this did not fire the console message. At the moment, I seem to be getting the following error message: ERROR TypeError: "result is null" 回答1: You can add a filter before

问题 Is there a simple way to bind a concatenation of StringProperty objects? Here is what I want to do: TextField t1 = new TextField(); TextField t2 = new TextField(); StringProperty s1 = new SimpleStringProperty(); Stringproperty s2 = new SimpleStringProperty(); Stringproperty s3 = new SimpleStringProperty(); s1.bind( t1.textProperty() ); // Binds the text of t1 s2.bind( t2.textProperty() ); // Binds the text of t2 // What I want to do, theoretically : s3.bind( s1.getValue() + " <some Text> " +

问题 I am trying to implement canActivate in Angular 2/4 using RxJS observables. I have already read another SO question on this. With the following code, my canActivate method works only once, when the app launches, but hello is never printed again when the isLoggedIn observable triggers new values. canActivate(): Observable<boolean> { return this.authService.isLoggedIn().map(isLoggedIn => { console.log('hello'); if (!isLoggedIn) { this.router.navigate(['/login']); } return isLoggedIn; }).first()

问题 I am trying to implement canActivate in Angular 2/4 using RxJS observables. I have already read another SO question on this. With the following code, my canActivate method works only once, when the app launches, but hello is never printed again when the isLoggedIn observable triggers new values. canActivate(): Observable<boolean> { return this.authService.isLoggedIn().map(isLoggedIn => { console.log('hello'); if (!isLoggedIn) { this.router.navigate(['/login']); } return isLoggedIn; }).first()