observerOnCompleted

observerOnCompleted is a method used in reactive programming, particularly within the RxJS library, to handle the successful completion of an observable sequence. When an observable has emitted all its intended values and no longer has any more data to send, it calls the onCompleted function on its observer.

The observer is an object that subscribes to an observable and defines how to react to the values emitted by that observable. An observer typically has three methods: onNext for handling emitted values, onError for handling errors, and onCompleted for handling the completion signal.

When an observable successfully completes, it signifies the end of the data stream. The onCompleted function is invoked on the observer to signal this termination. This allows the subscriber to perform any necessary cleanup actions, such as closing resources, updating UI elements, or initiating subsequent operations.

It is important to note that once an observable has called onCompleted, it will not emit any more values. Similarly, if onError is called, onCompleted will not be called thereafter. The onCompleted method does not receive any arguments, as its purpose is solely to signal the completion event. Using onCompleted effectively helps manage the lifecycle of reactive data streams and ensures proper handling of their termination.