I’m looking into Angular RxJs patterns and I don’t understand the difference between a BehaviorSubject and an Observable. From my understanding, a BehaviorSubject is a value that can change over time (can be subscribed to and subscribers can receive updated results). This seems to be the exact same purpose of an Observable. When would you … Read more
What is wrong with my Angular code? I am getting the following error: Cannot read property ‘remove’ of undefined at BrowserDomAdapter.removeClass <ol> <li *ngClass=”{active: step===’step1′}” (click)=”step=’step1′”>Step1</li> <li *ngClass=”{active: step===’step2′}” (click)=”step=’step2′”>Step2</li> <li *ngClass=”{active: step===’step3′}” (click)=”step=’step3′”>Step3</li> </ol> 22 s 22 Angular version 2+ provides several ways to add classes conditionally: type one [class.my_class] = “step === ‘step1′” … Read more
I am writing an Angular application and I have an HTML response I want to display. How do I do that? If I simply use the binding syntax {{myVal}} it encodes all HTML characters (of course). I need somehow to bind the innerHTML of a div to the variable value. 24 s 24 The correct … Read more
The situation I am trying to make what should be a very simple form in my Angular application, but no matter what, it never works. The Angular version Angular 2.0.0 RC5 The error Can’t bind to ‘formGroup’ since it isn’t a known property of ‘form’ The code The view <form [formGroup]=”newTaskForm” (submit)=”createNewTask()”> <div class=”form-group”> <label … Read more
Angular provides life cycle hook ngOnInit by default. Why should ngOnInit be used, if we already have a constructor? 2 27 The Constructor is a default method of the class that is executed when the class is instantiated and ensures proper initialisation of fields in the class and its subclasses. Angular, or better Dependency Injector … Read more
What is the difference between Promise and Observable in Angular? An example on each would be helpful in understanding both the cases. In what scenario can we use each case? 3 32
I’ve got the following error when launching my Angular app, even if the component is not displayed. I have to comment out the <input> so that my app works. zone.js:461 Unhandled Promise rejection: Template parse errors: Can’t bind to ‘ngModel’ since it isn’t a known property of ‘input’. (” <div> <label>Created:</label> <input type=”text” [ERROR ->][(ngModel)]=”test” … Read more
You need to import the map operator: [php]import ‘rxjs/add/operator/map'[/php] Or more generally: [php]import ‘rxjs/Rx’;[/php] Notice: For versions of RxJS 6.x.x and above, you will have to use pipeable operators as shown in the code snippet below: [php]import { map } from ‘rxjs/operators’; import { HttpClient } from ‘@angular/common/http’; // … export class MyComponent { constructor(private http: HttpClient) … Read more
