In this lesson you will learn how to create an Astro site.

What is Astro and what does it do Differently?

Before getting on with creating an Astro website in this Astro tutorial, let’s take a quick look at why you should consider using Astro. Astro is a tool for building content sites. It lets you bring your own framework. That means you can code up site content in React, Preact, Svelte, Vue, Solid, Lit, or a number of other frameworks. Of course, you can write your content in Markdown too (Astro has first-class support here). There is also an Astro markup language which looks much like HTML. Astro markup is fantastic for templating content, though we will see frameworks work well with Astro when you need interactivity.

Astro ships zero JavaScript by default, keeping your site lean. We will see that when you do want to add interactive, stateful content, you need to let Astro know. That is because Astro uses Partial Hydration: it only adds JavaScript for managing state to elements which require it. You might hear these interactive components being referred to as Islands of Interactivity. The pattern of large amounts of text or images and only sparse interactive islands is common on content sites. This makes Astro a marvelous choice for blogs, documentation, and other content rich websites.

Creating an Astro Site

To get going, you will need Node.js installed on your machine. We will use pnpm to install the packages, though the commands are similar if you prefer npm or yarn.

pnpm create astro@latest astro-beginners-tutorial

The fantastic CLI tool will help you in creating your Astro site. Select Empty from the presented project options. Next, choose the default, Yes, for installing dependencies. The tool will take a moment to download the project skeleton. Once it is done, change into the new project directory:

cd astro-beginners-tutorial

We will create a basic, collapsible menu component using React. Add an Astro integration to set up React in the project:

pnpm astro add react

Integrations are Astro packages that add necessary configuration files and peer dependencies for frameworks, tooling, or functionality. There are Svelte and Vue integrations, as well as Tailwind and sitemap ones.

For now, accept the default options to install packages and Astro configuration. We will take a closer look at the project files in a moment. For your next project, check the list of available Astro integrations; your favorite framework is probably included.

What’s Inside?

Let’s take a look at the anatomy of an Astro project. Here is the basic project layout:

Next, we see how to use the most important files and folders.

astro.config.mjs

This is the main Astro configuration file. You will see the astro add command above added React config for us here automatically.

public

The public folder is for files like favicons and robots.txt which will not need processing.

src/pages

src/pages is where you will add templates for your HTML pages. Typically, your HTML pages will be generated from Astro files here, though you can alternatively use Markdown or HTML.

tsconfig.json

This is your project TypeScript configuration file; Astro has out-of-the-box TypeScript support. Even if you prefer not to work in TypeScript, consider updating this file to support import aliases:

{
  "extends": "astro/tsconfigs/base",
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "~*": ["src/*"]
    },
    "jsx": "react-jsx",
    "jsxImportSource": "react"
  }
}

We will use this new alias below, when we create and then import the first React component.

Developing the Site

To start up the development server, run the command:

pnpm dev

You can now see the site running in your browser at http://localhost:3000/. Astro’s dev server supports Hot Module Replacement — changes you make to source files are instantly reflected in the browser. To see the site as it will be in production, you can run a build, and then start Astro’s preview server:

pnpm build
pnpm preview

For now, revert to the development server, so you can see the results of changes as you make them.

Astro Pages and Components

Astro files have a top, front matter, section, and a second markup part. The front matter section has --- delimiters top and bottom, and you add code to it in JavaScript or TypeScript. Use this section to prepare content you need to use in the markup. For example, you might want to manipulate a date, format a text string or import components from other files. We’ll use the front matter for an import here. Add this statement to the front matter in src/pages/index.astro:

---
import Menu from "~/components/Menu";
---

<!-- TRUNCATED... -->

That line will import the Menu component for us, though we have not yet created it; we will do so in a moment. Components let us compose and reuse interface units.

Creating an Astro Site: HTML Head

Notice the Astro template code (the part after the front matter) looks a lot like regular HTML:

<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <meta name="viewport" content="width=device-width" />
    <meta name="generator" content={Astro.generator} />
    <title>Astro</title>
  </head>
  <body>
    <h1>Astro</h1>
  </body>
</html>

You can see the familiar, html and head tags then the body. Much of this code is boilerplate, which will be the same on every site page. In the next lesson, we will move the html and head sections to a layout component. That way we will only need to update them in one place, for all pages, whenever we need to make changes.

Menu Component

Let’s now create that Menu component we mentioned, using React. Make a new src/components folder, and in there add a Menu.tsx file with this content:

import type { FC } from "react";
import { useState } from "react";

const Menu: FC = function Menu() {
  const [open, setOpen] = useState(false);

  const handleClick = () => {
    setOpen(!open);
  };

  // icons by Lucide: https://lucide.dev/

  return (
    <div className="menu-wrapper">
      <button
        aria-label={open ? "close menu" : "open menu"}
        type="button"
        onClick={handleClick}
      >
        {open ? (
          <svg
            role="img"
            aria-label="close"
            xmlns="http://www.w3.org/2000/svg"
            width="2em"
            height="2em"
            viewBox="0 0 24 24"
          >
            <path
              fill="none"
              stroke="currentColor"
              strokeLinecap="round"
              strokeLinejoin="round"
              strokeWidth="2"
              d="M18 6L6 18M6 6l12 12"
            ></path>
          </svg>
        ) : (
          <svg
            role="img"
            aria-label="menu"
            xmlns="http://www.w3.org/2000/svg"
            width="2em"
            height="2em"
            viewBox="0 0 24 24"
          >
            <path
              fill="none"
              stroke="currentColor"
              strokeLinecap="round"
              strokeLinejoin="round"
              strokeWidth="2"
              d="M4 12h16M4 6h16M4 18h16"
            ></path>
          </svg>
        )}
      </button>
      <nav className={open ? "menu menu-open" : "menu"}>
        <ul>
          <li>
            <a href="/">Home</a>
          </li>
          <li>
            <a href="/about">About</a>
          </li>
        </ul>
      </nav>
    </div>
  );
};

export default Menu;

Finally, we can update src/pages/index.astro to use this new component (we only imported it previously):

  <!-- ...TRUNCATED -->

  <body>
    <h1>Astro</h1>
    <Menu client:load />
  </body>

  <!-- TRUNCATED... -->

Jump over to your browser. Try clicking the menu button and you should see the icon change. We don’t yet have styling, so it looks a little odd, and the menu does not open or close. That said, the menu icon will change to a close icon when you click, and then revert to the original menu icon if you click again.

Why did we add client:load to the Menu component instance in index.astro? Try removing it, so you just have:

  <!-- ...TRUNCATED -->

  <body>
    <h1>Astro</h1>
    <Menu />
  </body>

  <!-- TRUNCATED... -->

Save the file. Now, when you click, nothing happens!

Astro ships zero JavaScript by default. Our menu will be an Astro Island of Interactivity and client:load is a directive to tell Astro to add the JavaScript for managing the component’s state.

Some other Astro directives

• client:idle: hydrate the component once the main thread is idle; might be used on an interactive search component

• client:visible: hydrate once the component is about to scroll into view; can help your page load faster initially, for example: only loading a JavaScript heavy widget just before it is visible

• client:media: lets you load components based on a CSS media query, often, you will prefer to use CSS paired with other directives instead

• client:only a little more advanced; the component will not be rendered when the site is built on the server but will still hydrate in the client browser

Check Astro documentation for full details on using these in your project.

File-based Routing

Astro uses file-based routing. We already saw that updating index.astro changes the output at http://localhost:3000/. Following the file-based routing pattern, creating src/pages/about.astro or src/pages/about.md results in Astro creating an HTML page at /about. Create src/pages/about.md with this content:

## Hello

Then, go to http://localhost:3000/about in your browser to see the new page. We will create more pages here later.

One last thing…

Did you notice the import statement in index.astro used the alias we defined in tsconfig.json? Without it, we would have written:

import Menu from "../components/Menu";

I guess it is a question of personal taste, however for larger projects with deeply nested components, you will probably prefer to stick with the alias.

Until next time!

That’s it for the first part of our tutorial: creating an Astro site. Stoked you made it to the end! I hope you found this start to the Astro Beginners’ Tutorial useful. We have had a look at what Astro is, and saw the main features. In the next installment, we will see Astro layouts in action and add some styles too!