What is subscribing and multicasting in Angular?

When someone subscribes then at that point in time the observable instance helps in the development of the values.

On the other hand, the process of broadcasting the list of several multiple subscribers and that too in a single execution this process is known as multicasting. The observable used here then here you have no registered listeners on the document. So what happens here is that by the use of the first listener we can send the values to each and every subscriber and that also we can keep reusing it.