Solid.js: The Lightweight, Reactive JavaScript Library You Need to Know About
Tags: solidjs, javascript, webdev, frontend
Published: 2023-03-09 23:16:30


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ckihkw2lxul3egvoeowc.png)


## Introduction

Front-end web development using JavaScript has become an essential part of building websites. Thanks to the many tools like libraries and frameworks available, developers can create more complex applications with less effort. One of the latest tools to join this list is [Solid.js](https://www.solidjs.com/).

## What is Solid.js?

[Solid.js](https://www.solidjs.com/) is a declarative JavaScript library for building user interfaces. It is built around the concept of reactive programming and provides a simple and efficient way to create interactive UI components. Solid.js is designed to be small, fast, and easy to learn. 

Solid.js is a relatively new library that is gaining popularity among front-end developers. Although it may have a smaller community and less comprehensive documentation compared to other established libraries like React, Solid.js offers several benefits. These include true reactivity, improved performance, better scalability, and a smaller size. As its community continues to grow, Solid.js is well-positioned to become a popular choice for front-end development in the future.

## Features of Solid.js

Solid.js offers several features that make it unique from other JavaScript libraries. Some of these features include:

- Reactive programming: Solid.js utilizes reactive programming to update the UI by tracking changes in the data and updating the DOM directly and accordingly - no need for a VDOM.
- JSX support: Solid.js supports JSX, which makes it easier to write and structure UI components in a more declarative way and can help improve code readability and maintenance.
- Suspense API: Solid.js offers a Suspense API that allows for better handling of asynchronous data fetching and rendering. This can help improve the perceived performance of web applications.

# Main differences with React

Both libraries aim to minimize unnecessary updates to the UI, but they use different methods to achieve this goal. React uses a virtual DOM, which allows it to efficiently compare the current state of the UI with the desired state and update only what needs to be changed. On the other hand, Solid.js uses reactive programming to detect when changes are made to the data that the UI depends on, and then updates the UI accordingly.

This approach can be more efficient than using a virtual DOM in certain situations, as it avoids the overhead of creating and manipulating a separate representation of the UI tree.

Take the following counter component as an example, written in both libraries:

```jsx
const Counter = () => {
  const [count, setCount] = createSignal(0);

  return (
    <div>
      <button onClick={() => setCount((count) => count + 1)}>+</button>
      <div>{count()}</div>
      <button onClick={() => setCount((count) => count - 1)}>-</button>
    </div>
  );
};
```

```jsx
const Counter = () => {
  const [count, setCount] = useState(0);

  return (
    <div>
      <button onClick={() => setCount((count) => count + 1)}>+</button>
      <div>{count}</div>
      <button onClick={() => setCount((count) => count - 1)}>-</button>
    </div>
  );
};
```

Although both libraries may appear similar at first glance, there are some key differences to consider

### Component rendering

Solid only renders a component once, even when there are updates to the component's data or props. This means that no matter how many times we press the increment button in the example above, the component function will never re-execute. Instead, it only updates the DOM element that uses a `signal` that has changed.

### Hooks

At first glance, you might assume that `createSignal` is a hook similar to `useState`. However, since the component never re-renders, hooks don't exist in Solid.

As a side effect of not having hooks, Solid's primitive functions (e.g. `createSignal`, `createEffect`, `onCleanup`, etc.) are not tied to the component like React's hooks.

For instance, to convert this count local state into a global state, we simply need to move the `createSignal` call outside of the component's scope.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ws62ep6su4xm5c29a3ed.jpeg)

### State management

Solid's state management is similar to React's, with the core difference being the existence of Signals. Signals are the core primitive of Solid, and they tell Solid when to update the DOM or re-execute effects.

The main difference between Signals and React's `useState` is that Signals are truly reactive. Whenever there is a change to a Signal's value, everyone that calls the Signal's getter will be re-executed.

```jsx
const Counter = () => {
  const [count, setCount] = createSignal(0);

  createEffect(() => {
    console.log("the count value is: ", count())
  })

  return (
    <div>
      <button onClick={() => setCount((count) => count + 1)}>+</button>
      <div>{count()}</div>
      <button onClick={() => setCount((count) => count - 1)}>-</button>
    </div>
  );
};

```

Using the above code as an example, we can see that `createEffect`, which is Solid's version of `useEffect`, does not take a dependencies array like `useEffect` does. This is because the effect is tracking changes to `count`.

## Benefits of Using Solid.js

Solid.js has several benefits that make it a great choice for building web applications. Some of these benefits include:

- Easy to learn: Solid.js is easy to learn and use, even for developers who are new to reactive programming.
- Improved performance: Solid.js utilizes atomic updates, which results in faster and more efficient performance compared to other JavaScript libraries.
- Better scalability: Solid.js is designed to be scalable, making it easier to handle large and complex applications.
- Small size: Solid.js is designed to be small and lightweight, with a size of only 7kb.

I would like to emphasize the performance and mention that Solid is one of the fastest UI libraries available.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/sk4qcmoycw6ulz4vqu4t.png)

## Solid Start

One of the key features of Solid is its own meta-framework, called [Solid Start](https://start.solidjs.com/getting-started/what-is-solidstart). This framework is similar to [Next.js](https://nextjs.org/) in React and provides developers with a robust set of tools to build apps quickly and efficiently.

Solid Start offers several advantages to developers. For example, it simplifies the process of building and deploying apps by providing a clear and easy-to-use structure for organizing code, making it an ideal starting point for developers who are new to Solid. Additionally, it includes a range of pre-built components that developers can use to quickly add functionality to their apps.

Also, it is maintained by the core team of Solid, as opposed to Next.js which is maintained by [Vercel](https://vercel.com/).

## Drawbacks of Solid.js

- Limited community: Solid.js is a relatively new library, which means that it has a smaller community compared to other established libraries like React or Vue.js. This can make it harder to find resources and support when encountering issues.
- Lack of third-party packages: Solid.js has a limited number of third-party packages available compared to other libraries. This can make it harder to find the right tools and components for your specific needs.
- Limited documentation: As a relatively new library, Solid.js has limited documentation compared to other established libraries like React or Vue.js. This can make it harder for developers to get started and learn how to use the library effectively.

## Future of Solid.js

Solid.js is a new library that many developers are starting to use. It is getting more popular and will probably get better in the future. It could become a popular choice for making fast and efficient web applications.

## Conclusion

Solid.js is a powerful JavaScript library that offers several benefits for front-end development. Its reactive programming approach, JSX support, and server-side rendering capabilities make it an excellent choice for building web applications. Whether you're looking to improve the performance and efficiency of your web applications or just learn a new framework, Solid.js is definitely worth checking out.