What is a BehaviorSubject?

In this video, we got a high level overview of the BehaviorSubject.

The reason we want to begin using the BehaviorSubject is because we want full control of what is being emmitted from our service. Using the next() method on our BehaviorSubject we can choose what we want emmitted.

And we are using the BehaviorSubject instead of just a Subject because the BehaviorSubject has the ability to keep track of the last emmitted value. This means we will have easy access to what was previously emmitted. We will be able to easily modify that data that had been previously emmitted.