Angular Signals Have Changed Angular Forever — Here's the Complete Guide

Angular finally has fine-grained reactivity. Signals replace Zone.js and make change detection predictable and fast. What Are Angular Signals? Signals are reactive primitives that notify Angular when their value changes. Instead of Zone.js checking everything, Angular only updates what actually changed. Creating Signals import { Component , signal , computed , effect } from ' @angular/core ' ; @ Component ({ selector : ' app-counter ' , template : ` <p>Count: {{ count() }}</p> <p>Doubled: {{ doubled() }}</p> <button (click)="increment()">+</button> <button (click)="reset()">Reset</button> ` }) export class CounterComponent { count = signal ( 0 ); doubled = computed (() => this . count () * 2 ); constructor () { effect (() => { console . log ( ' Count changed: ' , this . count ()); }); } increment () { this . count . update ( c => c + 1 ); } reset () { this . count . set ( 0 ); } } Signal API // Create const name = signal ( ' Alice ' ); const user = signal ({ name : ' Alice ' , age : 30