Why does Angular use observables
Angular makes use of observables as an interface to handle a variety of common asynchronous operations. For example: The HTTP module uses observables to handle AJAX requests and responses. The Router and Forms modules use observables to listen for and respond to user-input events.
What is observable and observer in Angular
Observable are just that — things you wish to observe and take action on. Angular uses the Observer pattern which simply means — Observable objects are registered, and other objects observe (in Angular using the subscribe method) them and take action when the observable object is acted on in some way.
What is observables in RXJS
Advertisements. An observable is a function that creates an observer and attaches it to the source where values are expected from, for example, clicks, mouse events from a dom element or an Http request, etc.
What is observable and Observer
Observer : Any object that wishes to be notified when the state of another object changes. Observable : Any object whose state may be of interest, and in whom another object may register an interest.
Why do we need observables
Observables provide support for passing messages between parts of your application. They are used frequently in Angular and are a technique for event handling, asynchronous programming, and handling multiple values.
What is observable in Angular interview questions
An observable is like a Stream. It is used to pass zero or more events where the callback is called for each event. Observable is always preferred over Promise because it provides all the features of Promise and more. By using an observable, we can handle single or multiple events.
What is RxJS
What is NGRX and RxJS
Ngrx is a group of Angular libraries for reactive extensions. Ngrx/Store implements the Redux pattern using the well-known RxJS observables of Angular 2. It provides several advantages by simplifying your application state to plain objects, enforcing unidirectional data flow, and more.
What is map in Angular
The Angular observable Map operator takes an observable source as input. It applies a project function to each of the values emitted by the source observable and transforms it into a new value. It then emits the new value to the subscribers.
What is Angular observable pipe
The pipe method of the Angular Observable is used to chain multiple operators together. We can use the pipe as a standalone method, which helps us to reuse it at multiple places or as an instance method. In this tutorial, we will take a look at the pipe and learn how to use it in an Angular Application.
What is a decorator in Angular
Decorators are a design pattern that is used to separate modification or decoration of a class without modifying the original source code. In AngularJS, decorators are functions that allow a service, directive or filter to be modified prior to its usage.
Should I use Promise or Observable
Often Observable is preferred over Promise because it provides the features of Promise and more. With Observable it doesn't matter if you want to handle 0, 1, or multiple events. You can utilize the same API in each case. Observable also has the advantage over Promise to be cancellable.