If your Angular application already uses NgRx, you know the value of writing good reducers and using one-way data flow. However, that knowledge may not be enough to keep the biggest form in your app from being a rat’s nest of FormGroups and related logic. Forget keeping components under 50 lines of code - your form logic alone blows past that.
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Angular 
If you're dealing with forms in Angular on a regular basis one of the most powerful things you can learn is how to use the Control Value Accessor interface. The CVA interface is a bridge between FormControls and their elements in the DOM. A component extending the CVA interface can create a custom form control that behaves the same as a regular input or radio button.
Jennifer Wadella
Angular
Angular's Reactive Forms give us immense capabilities with its robust API, but the learning curve can be a bit steep from plain old template-driven forms that many are used to. This quick guide will explain Angular's main form elements and how to combine them, nest them, and dynamically create them in almost any scenario.
Jennifer Wadella