Observer
An object interface that defines a set of callback functions a user can use to get notified of any set of Observable {@link guide/glossary-and-semantics#notification | notification} events.
For more info, please refer to {@link guide/observer | this guide}.
§Properties
A callback function that gets called by the producer if and when it has no more
values to provide (by calling next callback function). This means that no error
has happened. This callback can't be called more than one time, it can't be called
if the error callback function have been called previously, nor it can't be called
if the consumer has unsubscribed.
For more info, please refer to {@link guide/glossary-and-semantics#complete | this guide}.
A callback function that gets called by the producer if and when it encountered a
problem of any kind. The errored value will be provided through the err parameter.
This callback can't be called more than one time, it can't be called if the
complete callback function have been called previously, nor it can't be called if
the consumer has unsubscribed.
For more info, please refer to {@link guide/glossary-and-semantics#error | this guide}.
A callback function that gets called by the producer during the subscription when
the producer "has" the value. It won't be called if error or complete callback
functions have been called, nor after the consumer has unsubscribed.
For more info, please refer to {@link guide/glossary-and-semantics#next | this guide}.