Faster Angular Applications – Understanding Differs. Developing a Custom IterableDiffer

In this article we’ll take a look at another Angular abstraction – the differs and more specifically the IterableDiffer; we’ll explain what the differs are and how the framework uses them internally. After that, we’ll take a look at how NgForOf works and design a custom data structure optimized for the directive. Finally, we’ll develop a custom differ which will speed up the change detection mechanism of Angular when working with large collections.

Link: http://blog.mgechev.com/2017/11/14/angular-iterablediffer-keyvaluediffer-custom-differ-track-by-fn-performance/