Angular 19 — What’s up with Signals?

The Signals that were Developer Preview in Angular v17 are now stable 🙂‍↕️

These include the view/content queries (viewChild, viewChildren, contentChild, contentChildren) and also output.
If you want a refresher on them, check out this post:
https://lnkd.in/dN_kPEhu

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What’s new in Angular 19?

🎗 linkedSignal()

Remember computed() signals? linkedSignal() works similarly, but it’s writable.

It derives its value from another signal

You can also manually update it anytime you want

Example:

const count = linkedSignal(() => list().length);
count.set(0); // You can manually set it now, even though it’s derived

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The next three signals are designed for reactive handling of async data, providing signals for loading, error, and value states.

🎗 resource()

A reactive API for managing async data (HTTP calls, loading, etc).

Provides loading, error, and value states as Signals

Supports reload and abort unnecessary operations (abortSignal)

Usage:

things.value();
things.error();
things.loading();

🎗 httpResource()

A specialized version of resource() for HTTP requests using Angular HttpClient.
Instead of building a resource from scratch:

const things = httpResource({
request: () => this.http.get('/api/things'),
});

Access states the same way:

things.value();
things.error();
things.loading();

🎗 rxResource()

For when you want to keep using RxJS Observables within Signals.
Instead of manually converting an Observable to a Signal (toSignal()), it wraps it automatically.

things.value();
things.error();
things.loading();

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🐧 Quick comparison

resource() → base API, you can build any resource (not just HTTP)

httpResource() → ready-to-use specialization for HTTP requests using Angular HttpClient

rxResource() → specialization for RxJS Observables to work seamlessly in the Signals ecosystem

⚠️ All these new Signals in Angular 19 are Developer Preview.

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And that’s it!
If you’re still unsure how it works, check out this post:
https://lnkd.in/dvFG2P3d