Solid.js Introduction and Installation — Reactive UI Framework

In this tutorial, you will learn about Solid.js Introduction and Installation. We cover key concepts, practical examples, and best practices to help you master this topic.

Learn Solid.js: understand fine-grained reactivity, install the framework, create a project, and explore the core concepts of this high-performance UI library.

In this lesson, you'll install Solid.js, create a project, understand its reactivity model, and compare it to other UI frameworks. Solid.js is a reactive JavaScript library that compiles JSX into real DOM operations without a virtual DOM.

What You'll Learn

How to create a Solid.js project, understand signals and reactivity, and recognize what makes Solid.js different from React.

Why It Matters

Solid.js delivers top-tier performance by eliminating virtual DOM overhead. Components render once, and only the specific DOM nodes bound to changing signals update.

Real-World Use

Doda Browser uses Solid.js for its tab management UI because real-time tab updates need sub-millisecond reactivity to feel instant.

flowchart LR
    A[Install] --> B[Create Project]
    B --> C[Signals]
    C --> D[Effects]
    D --> E[Memos]
    E --> F[DOM Updates]
    style C fill:#2c4f7c,color:#fff

Installation

npm init solid@latest my-solid-app
cd my-solid-app
npm install
npm run dev

Choose the "JavaScript" template for learning. The dev server starts at http://localhost:5173.

Project Structure

my-solid-app/
├── src/
│   ├── App.jsx
│   ├── App.module.css
│   └── index.jsx
├── index.html
├── package.json
└── vite.config.js

Solid.js uses Vite for development and builds.

Your First Component

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

export default function App() {
  return <Hello />;
}

Output: The page renders "Hello from Solid.js!" with blazing-fast performance. The component renders once and never updates because there's no reactive state.

Common Mistakes

1. Confusing Solid.js with React: Solid.js looks like React but works differently. Signals replace useState, and there's no virtual DOM.
2. Forgetting to call signals as functions: count() reads the value, count returns the getter function.
3. Not using .jsx extension: Solid.js components use .jsx or .tsx extensions. Plain .js files don't support JSX.
4. Installing React packages: Solid.js has its own ecosystem. React packages won't work directly.
5. Expecting React DevTools: Solid.js has its own DevTools. React DevTools don't detect Solid.js components.

Practice Questions

1. What command creates a new Solid.js project? Answer: npm init solid@latest my-solid-app. Choose a template from the CLI prompts.

2. How does Solid.js differ from React? Answer: Solid.js uses fine-grained reactivity with signals and no virtual DOM. React uses a virtual DOM with component-level re-rendering.

3. What is the default dev server port? Answer: Port 5173 (Vite's default). Access at http://localhost:5173.

4. What is a signal? Answer: A reactive primitive that holds a value and notifies dependents when the value changes.

Challenge

Create a Solid.js project, explore the default template files, and identify the role of each file (App.jsx, index.jsx, main.jsx, vite.config.js).

Mini Project

Build a simple profile card component that displays a name, title, and avatar image. Style it with CSS modules and export it from App.jsx.

FAQ

What's Next

Learn about Solid.js Signals to understand the foundation of Solid.js reactivity.