AsyncSubject is a variant of a Subject which keeps the last value emitted by a source observable before completion and sends it to all new subscriptions and as soon as you call complete() method, it sends the last emitted value to all current subscribers and its future subscribers.
Async Subject only hold single value unlike Behaviour and ReplaySubject. So we can related Async Subject with promise because promises also hold single value and on completion it send the data, the major difference is that promise are eager and Observables (Async Subject) is lazy , it means promises don't need any subscriber for its execution, it execute immediately but on another hand Observables are lazy it mean they need subscriber to start execution
Async Subject could be useful for fetching and caching (one-shot) resources, since generally http.get will emit one response then complete.
Please watch my other video that I have created to explain the functionality of Subject and its variants in RxJS, so that you can understand it easily in Angular.
RxJS Subject: • RxJS Subject | What is...
RxJS BehaviorSubject : • BehaviorSubject | Beha...
RxJS Replay Subject: • ReplaySubject | Replay...
Angular Subject and BehaviorSubjet: • Subject and BehaviorSu...
Promises vs Observables: • Promises vs Observable...
Promises vs Observables shorts: • Promise vs Observable ...
We have used @Input and @output decorator when data need to pass from parent to child and vice a versa, But syncing your data across the components which don't have any parent-child relationship, there services are the solution.
@Input Decorator: • Communicate from Paren...
@Output Decorator : • Communicate from Child...
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I have used below FAKE API in demo to illustrate the AsyncSubject:
restcountries....
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25 авг 2024