solid-js

What is solid-js?

Solid.js is a declarative JavaScript library for building user interfaces. It focuses on fine-grained reactivity, which allows for highly efficient updates and minimal re-renders. Solid.js is designed to be fast and simple, providing a reactive programming model that is easy to understand and use.

What are solid-js's main functionalities?

Reactive State Management

Solid.js uses fine-grained reactivity for state management. The `createSignal` function creates a reactive state that updates the UI efficiently when the state changes.

import { createSignal } from 'solid-js';

function Counter() {
  const [count, setCount] = createSignal(0);
  return (
    <div>
      <button onClick={() => setCount(count() + 1)}>Increment</button>
      <p>Count: {count()}</p>
    </div>
  );
}

JSX Support

Solid.js supports JSX, allowing you to write HTML-like syntax within JavaScript. This makes it easy to create and manage UI components.

import { render } from 'solid-js/web';

function App() {
  return (
    <div>
      <h1>Hello, Solid.js!</h1>
    </div>
  );
}

render(() => <App />, document.getElementById('root'));

Component Composition

Solid.js allows for easy component composition. You can create reusable components and pass data to them via props.

function Greeting(props) {
  return <h1>Hello, {props.name}!</h1>;
}

function App() {
  return (
    <div>
      <Greeting name="Solid.js" />
    </div>
  );
}

Direct DOM Manipulation

Solid.js provides direct DOM manipulation capabilities. The `onCleanup` function allows you to perform cleanup tasks, such as clearing intervals, when a component is unmounted.

import { onCleanup } from 'solid-js';

function Timer() {
  let timerId;
  const [time, setTime] = createSignal(0);

  const startTimer = () => {
    timerId = setInterval(() => setTime(time() + 1), 1000);
  };

  onCleanup(() => clearInterval(timerId));

  return (
    <div>
      <p>Time: {time()}</p>
      <button onClick={startTimer}>Start Timer</button>
    </div>
  );
}

Other packages similar to solid-js

react

React is a popular JavaScript library for building user interfaces. It uses a virtual DOM and a component-based architecture. Compared to Solid.js, React has a larger ecosystem and community but may have more overhead due to its virtual DOM.

vue

Vue.js is a progressive JavaScript framework for building user interfaces. It features a reactive data binding system and a component-based architecture. Vue.js is similar to Solid.js in its reactivity model but offers more built-in features and a larger ecosystem.

svelte

Svelte is a compiler that converts declarative components into efficient imperative code that directly manipulates the DOM. Unlike Solid.js, Svelte does not use a virtual DOM and compiles components at build time, resulting in highly optimized and fast applications.

README

Solid is a declarative JavaScript library for creating user interfaces. It does not use a Virtual DOM. Instead it opts to compile its templates down to real DOM nodes and wrap updates in fine grained reactions. This way when your state updates only the code that depends on it runs.

Key Features

• Real DOM with fine-grained updates (No Virtual DOM! No Dirty Checking Digest Loop!).
• Declarative data
  • Simple composable primitives without the hidden rules.
  • Function Components with no need for lifecycle methods or specialized configuration objects.
  • Render once mental model.
• Fast! Almost indistinguishable performance vs optimized painfully imperative vanilla DOM code. See Solid on JS Framework Benchmark.
• Small! Completely tree-shakeable Solid's compiler will only include parts of the library you use.
• Supports and is built on TypeScript.
• Supports modern features like JSX, Fragments, Context, Portals, Suspense, Streaming SSR, Progressive Hydration, Error Boundaries and Concurrent Rendering.
• Webcomponent friendly and can author Custom Elements
  • Context API that spans Custom Elements
  • Implicit event delegation with Shadow DOM Retargeting
  • Shadow DOM Portals
• Transparent debugging: a <div> is just a div.

Top 5 Things You Should Know about Solid

The Gist

import { render } from "solid-js/web";

const HelloMessage = props => <div>Hello {props.name}</div>;

render(() => <HelloMessage name="Taylor" />, document.getElementById("hello-example"));

A Simple Component is just a function that accepts properties. Solid uses a render function to create the reactive mount point of your application.

The JSX is then compiled down to efficient real DOM expressions:

import { render, template, insert, createComponent } from "solid-js/web";

const _tmpl$ = template(`<div>Hello </div>`);

const HelloMessage = props => {
  const _el$ = _tmpl$.cloneNode(true);
  insert(_el$, () => props.name);
  return _el$;
};

render(
  () => createComponent(HelloMessage, { name: "Taylor" }),
  document.getElementById("hello-example")
);

That _el$ is a real div element and props.name, Taylor in this case, is appended to its child nodes. Notice that props.name is wrapped in a function. That is because that is the only part of this component that will ever execute again. Even if a name is updated from the outside only that one expression will be re-evaluated. The compiler optimizes initial render and the runtime optimizes updates. It's the best of both worlds.

Want to see what code Solid generates:

Try it Online

Getting Started

npm init solid <project-type> <project-name> is available with npm 6+.

You can get started with a simple app with the CLI with by running:

> npm init solid app my-app

Or for a TypeScript starter:

> npm init solid app-ts my-app

Or you can install the dependencies in your own project. To use Solid with JSX (recommended) run:

> npm install solid-js babel-preset-solid

The easiest way to get setup is add babel-preset-solid to your .babelrc, or babel config for webpack, or rollup:

"presets": ["solid"]

For TypeScript remember to set your TSConfig to handle Solid's JSX by:

"compilerOptions" {
  "jsx": "preserve",
  "jsxImportSource": "solid-js",
}

Check out these two introductory articles by @aftzl: Understanding Solid: Reactivity Basics
Understanding Solid: JSX

Documentation

• Reactivity
• State
• JSX Rendering
• Components
• Styling
• Context
• Suspense
• API
• FAQ
• Comparison with other Libraries
• Storybook

Resources

• Examples
• Articles
• Projects

No Compilation?

Dislike JSX? Don't mind doing manual work to wrap expressions, worse performance, and having larger bundle sizes? Alternatively in non-compiled environments you can use Tagged Template Literals or HyperScript.

You can run them straight from the browser using SkyPack:

<html>
  <body>
    <script type="module">
      import { createSignal, onCleanup } from "https://cdn.skypack.dev/solid-js";
      import { render } from "https://cdn.skypack.dev/solid-js/web";
      import html from "https://cdn.skypack.dev/solid-js/html";

      const App = () => {
        const [count, setCount] = createSignal(0),
          timer = setInterval(() => setCount(count() + 1), 1000);
        onCleanup(() => clearInterval(timer));
        return html`<div>${count}</div>`;
      };
      render(App, document.body);
    </script>
  </body>
</html>

Remember you still need the corresponding DOM Expressions library for these to work with TypeScript. Tagged Template Literals Lit DOM Expressions or HyperScript with Hyper DOM Expressions.

Browser Support

The last 2 versions of modern evergreen browsers and Node LTS.

Community

Come chat with us on Discord

Contributors

Open Collective

Support us with a donation and help us continue our activities. [Contribute]

Sponsors

Become a sponsor and get your logo on our README on GitHub with a link to your site. [Become a sponsor]

Status

Solid is mostly feature complete for its v1.0.0 release. The next releases will be mostly bug fixes and API tweaks on the road to stability.