Effortless State Management with Preact Signals: A Lightweight and High-Performance Solution

State Management with Preact Signals

Preact is a lightweight alternative to React, and it comes with its own state management library called Signals. Signals is designed to be fast and efficient, with a simple API that makes it easy to use.

What are Signals?

A signal is an object with a .value property that holds some value. When the value of the signal changes, any components that are subscribed to the signal will automatically update. Signals can be used to manage state in a Preact application, and they can also be used with other frameworks and libraries.

How do Signals Work?

When a component accesses the value of a signal, it automatically subscribes to the signal. If the value of the signal changes, the component will automatically re-render with the new value. This approach eliminates the need for manual dependency tracking and updates, making it easier to manage state in complex applications.

Benefits of Using Signals

Signals offer several benefits over traditional state management approaches. They are:

• Lazy by default: Only signals that are currently being used are observed and updated.
• Optimal updates: If a signal’s value hasn’t changed, components and effects that use that signal’s value won’t be updated.
• Optimal dependency tracking: The framework tracks which signals everything depends on, eliminating the need for manual dependency arrays.
• Direct access: Accessing a signal’s value in a component automatically subscribes to updates without the need for selectors or Hooks.

Using Signals in a Preact Application

To use Signals in a Preact application, you can install the @preact/signals package using npm. Then, you can import the signal function and use it to create signals in your application.

Here is an example of how to use Signals in a Preact application:

“`javascript
import { signal } from ‘@preact/signals’;

const count = signal(0);

function Counter() {
return (

);
}
“`

Deriving State with Computed Signals

In addition to basic signals, Preact Signals also provides a computed function that allows you to derive state from other signals. Computed signals are read-only and automatically update when any of the signals they depend on change.

Here is an example of how to use computed signals:

“`javascript
import { signal, computed } from ‘@preact/signals’;

const user = signal(null);

const isLoggedIn = computed(() => user.value !== null);

function Header() {
if (isLoggedIn.value) {
return

Welcome, {user.value.name}!

;
} else {
return

Please log in.

;
}
}
“`

Comparison to Other State Management Solutions

Preact Signals is a relatively new state management solution, but it has already gained popularity due to its simplicity and performance. Here is a comparison of Preact Signals to other popular state management solutions:

• Redux: Redux is a more mature state management solution with a larger community and more features. However, it can be more complex to set up and use.
• Zustand: Zustand is another popular state management solution that is known for its simplicity and performance. However, it may not be as suitable for large-scale applications.

Overall, Preact Signals is a great choice for managing state in Preact applications, especially for smaller to medium-sized projects. Its simplicity and performance make it an attractive option for developers who want to focus on building their application rather than managing state.