Deep Dive into Angular Signals

Angular Signals represent a fundamental shift in how we handle reactivity in Angular applications. This powerful new API brings fine-grained reactivity to Angular, making your applications more efficient and easier to reason about.

Introduction

Signals are a new reactive primitive that will fundamentally change how Angular applications are built. They provide a way to define reactive values that notify interested consumers when they change.

What are Signals?

A signal is a wrapper around a value that can notify interested consumers when that value changes. Signals can contain any value, from simple primitives to complex data structures.

Creating Signals

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

const count = signal(0);
const user = signal({ name: 'Alice', age: 30 });

Computed Signals

Computed signals derive their value from other signals:

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

const firstName = signal('John');
const lastName = signal('Doe');
const fullName = computed(() => `${firstName()} ${lastName()}`);

Effects

Effects run side effects when signals change:

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

effect(() => {
  console.log(`The count is: ${count()}`);
});

Benefits of Signals

1. Fine-grained reactivity - Only update what actually changed
2. Better performance - Skip unnecessary change detection
3. Simpler mental model - No zone.js complexity
4. Type safety - Full TypeScript support
5. Glitch-free - Computed values update atomically

Signals vs RxJS

While RxJS excels at handling async events and complex operators, Signals are perfect for synchronous state management:

• Signals: Best for local component state
• RxJS: Best for async operations, HTTP, events

Conclusion

Angular Signals mark a new era in Angular development. By embracing this reactive primitive, you'll write cleaner, more efficient code that's easier to understand and maintain.

Written with ❤️ using Claude Blog