Filter a stream to exclude empty values
Although ‘epics’ in RxJS are often described as ‘actions in, actions out’, there may be times when you need to ‘bail out’ of an action, or to just ignore the current one given some condition. By learning about RxJS’s
filter Operator, we’ll see how easy it is to do ‘nothing’ when you need to. We’ll also see how the composition techniques available in RXJS allow us to control the UI in a declarative manner.