signals-react

signals-react is a React hook library designed to offer a reactive state management solution inspired by signal mechanisms, but tailored specifically for React applications. By leveraging the rxjs observables, it introduces a robust and adaptable approach to managing state changes within components. This library enables developers to create signals, compute derived signals, and manage side effects seamlessly.

Example with global state

Example with local state

Installation

To integrate signals-react into your project, install it through npm by executing:

npm install signals-react

Usage

Begin by importing createSignal from signals-react to initiate signal creation and management in your React app.

Creating a Signal

import { createSignal } from 'signals-react';

const countSignal = createSignal(0); 
// Initializes a global signal with an initial value of 0.

const CounterComponent = () => {
  const value = countSignal.useValue(); 
  // Subscribes to signal changes, rerendering the component accordingly.

  return (
    <div>
      <p>Current count: {value}</p>
      <button onClick={() => {
        countSignal.setValue((prev) => prev + 1)
      }}>Increment</button>
    </div>
  );
};

Rendering Optimizations

Utilize the signal directly within JSX to minimize component subscriptions and unnecessary re-renders. Only the signal's content will be updated:

const countSignal = createSignal(0);

function Unoptimized() {
  // Triggers component re-renders on countSignal changes.
  const value = countSignal.useValue();
  return <p>{value}</p>;
}

function Optimized() {
  // Updates text automatically without rerendering the component.
  return <p>{countSignal}</p>;
}

Local State Management with Signals

While most application states are managed globally, components often require their own internal state. For such cases, signals-react offers useSignal and useComputed hooks for creating and computing signals within components:

import { useSignal } from "signals-react";

function Counter() {
  const count = useSignal(0);
  const double = count.useComputed(value => value * 2);

  return (
    <div>
      <p>Current count: {count}, double: {double}</p>
      <button onClick={() => count.setValue(count.peek() + 1)}>Increment</button>
    </div>
  );
}

Advanced Features

Using peek()

The peek() method enables reading the current signal value without subscription or triggering re-renders, ideal for event-based updates:

function Counter() {
  const count = useSignal(0);
  return (
    <div>
      <button onClick={() => count.setValue(count.peek() + 1)}>Increment</button>
    </div>
  );
}

Using compute

The compute method facilitates the creation of ComputedSignals from existing signals, allowing for dynamic and reactive derived states:

const celsiusSignal = createSignal(0);
const fahrenheitSignal = celsiusSignal.compute(c => c * 9 / 5 + 32);

celsiusSignal.setValue(36); // Automatically updates fahrenheitSignal.

const TemperatureConverter = () => {
  return (
    <div>
      <p>Celsius: {celsiusSignal.useValue()}</p>
      <p>Fahrenheit: {fahrenheitSignal.useValue()}</p>
    </div>
  );
};

This method enhances state management by enabling efficient and logical reactive transformations, streamlining the development of complex reactive systems.

License

signals-react is distributed under the MIT License. For more details, refer to the LICENSE file in the repository.