What changes came to Angular with the introduction of Signals, and why is it necessary?

With the introduction of Signals in Angular, a new reactive state management model was introduced, based on change tracking through signals — objects that store a value and notify subscribers when it changes.

This allows Angular to optimize UI updates, making them more precise and efficient, reducing unnecessary checks and re-renders. Signals simplify reactive programming in Angular, make the code cleaner and more understandable, and also improve application performance.

Example of using Signals in Angular:

import { signal } from '@angular/core';

const count = signal(0);

function increment() {
  count.set(count() + 1);
}

// The component will automatically update when count changes

Thus, Signals are a step towards more reactive and efficient Angular.