Change Detection the magic behind Angular that automatically recognizes when changes happen. That’s either due to manual triggering or through asynchronous events. Once a change is detected, it iterates through the various Angular Components and triggers a refresh. Usually it is very fast, however - especially in larger apps - it might trigger lots of computations and thus block the main browser thread. In this lesson we’re going to learn how to optimize Angular’s change detection mechanism by reducing the amount of components it needs to update and via pure pipes.