What is BehaviorSubject class in RxJS?

BehaviorSubject is a type of Subject in RxJS which represents an observable with its current value. It stores the latest value emitted to its subscribers and whenever a new subscriber subscribes, it immediately emits the current value to the subscriber. This makes BehaviorSubject a very powerful tool for managing state and data flow in applications.

When working with Angular, BehaviorSubject is commonly used for managing the state of components and sharing data between them. It provides a way to create a data source that can be easily subscribed to and updated from different parts of the application.

One of the key features of BehaviorSubject is that it maintains the latest value, even if there are no subscribers. This means that any new subscriber will immediately receive the last value emitted by the BehaviorSubject, which can be very useful for initializing component state or sharing data between different components.

Here is an example of how to create and use a BehaviorSubject in Angular:

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In the example above, we create a new instance of BehaviorSubject with an initial value of ‘initial value’. We then subscribe to the BehaviorSubject and log the current value. Finally, we update the value of the BehaviorSubject to ‘new value’ using the next() method.

Overall, BehaviorSubject is a powerful tool for managing state and data flow in applications, especially when working with Angular and RxJS. It provides a way to create a data source that can be easily subscribed to and updated from different parts of the application, making it a valuable asset for any developer.