Building handcrafted forms can be costly and time-consuming, especially if you need a great number of them, they're similar to each other, and they change frequently to meet rapidly changing business and regulatory requirements.
Reactive forms provide a model-driven approach to handling form inputs whose values change over time. Reactive forms use an explicit and immutable approach to managing the state of a form at a given point in time. Each change to the form state returns a new state, which maintains the integrity of the model between changes. Reactive forms are built around observable streams, where form inputs and values are provided as streams of input values, which can be accessed synchronously.