A listener may well be an implementation of the observer pattern . A listener is essentially waiting for an event to occur on a given object, which is what an observer does.
Read moreIs observer an MVC?
The Observer Pattern is the foundation of the Model View Controller (MVC) pattern , in which a view is updated automatically whenever the model’s state changes. In the . NET Framework, delegates with events are an implementation of the Observer pattern.
Read moreIs MutationObserver slow?
Good answer! Yes, it’s finally slower by just 10% or even less in recent versions of Chrome . @Bergi, it’s for the case when processing is complex and takes a lot of time. MutationObserver runs in a microtask queue so multiple callbacks may still reside in one task, which can lead to very long paint frames and jank.
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