Outline
All of this project's code can be found in the First Look monorepo on my GitHub.
Introduction
Astro is an open source web framework influenced by the Islands Architecture. It was created by Fred K. Schott, Matthew Phillips, Nate Moore, and Drew Powers as an outgrowth of the work being done simultaneously on Snowpack and Skypack.
It supports a variety of UI integrations including React, Svelte, Vue, Solid, and many more. The framework deserves a fair amount of credit for bringing partial hydration and the concept of "Islands of Interactivity" to the mainstream web development conversation.
Partial Hydration
I have an entirely separate, lengthy article about this, but here's the summary. The conversation had been present but on the fringes for well over a decade. The first framework that fully supported these techniques, Marko, was created in 2014 but remained the odd duck out until around 2019.
However, in the last 2 years there has been an influx of frameworks drawing on similar motivations and prior art including Slinkity, Elder.js, îles, and Qwik. Fred K. Schott describes the architecture and goals of Astro in Introducing Astro: Ship Less JavaScript (June 8, 2021):
Astro works a lot like a static site generator. If you have ever used Eleventy, Hugo, or Jekyll (or even a server-side web framework like Rails, Laravel, or Django) then you should feel right at home with Astro.
In Astro, you compose your website using UI components from your favorite JavaScript web framework (React, Svelte, Vue, etc). Astro renders your entire site to static HTML during the build. The result is a fully static website with all JavaScript removed from the final page.
While there are plenty of frameworks based on React, Vue, and Svelte that let you render components to static HTML during build time, if you want to hydrate these projects on the client then you have to ship an entire bundle of dependencies along with the static HTML. Astro, on the other hand, includes the ability to load just a single component and its dependencies where that component is needed.
Client Directives
Astro includes five client:*
directives to hydrate components on the client at runtime. A directive is a component attribute that tells Astro how your component should be rendered.
Directive | Description |
---|---|
<Component client:load /> |
Hydrates the component on page load. |
<Component client:idle /> |
Hydrates the component as soon as main thread is free. |
<Component client:visible /> |
Hydrates the component as soon as the element enters the viewport. |
<Component client:media={QUERY} /> |
Hydrates the component as soon as the browser matches the given media query. |
<Component client:only /> |
Hydrates the component at page load, similar to client:load . The component will be skipped at build time. |
Create Project
This tutorial will build up an Astro project from scratch instead of using any of the starter templates because I believe that is a better way to learn how a framework works, but the templates are really fantastic.
Start by creating a new directory for your project and initializing a package.json
file.
mkdir ajcwebdev-astro
cd ajcwebdev-astro
yarn init -y
Install Astro Dependency
Install the astro
dependency and create .gitignore
file.
yarn add -D astro
echo 'node_modules\ndist\n.DS_Store' > .gitignore
Add CLI Commands
Add the following scripts to package.json
.
{
"name": "ajcwebdev-astro",
"version": "1.0.0",
"main": "index.js",
"license": "MIT",
"devDependencies": {
"astro": "^1.0.0-beta.28"
},
"scripts": {
"dev": "astro dev",
"start": "astro dev",
"build": "astro build",
"preview": "astro preview"
}
}
All commands are run from the root of the project.
-
yarn dev
andyarn start
both start a local development server onlocalhost:3000
. -
yarn build
builds a production site to./dist
. -
yarn preview
previews the build locally before deploying.
Create a Page
Astro looks for .astro
or .md
files in the src/pages
directory. Each page is exposed as a route based on its file name. Static assets such as images can be placed in the public
directory.
mkdir -p src/pages public
touch src/pages/index.astro
Inside the src/pages
directory we created an index.astro
file.
---
// src/pages/index.astro
let title = 'ajcwebdev-astro'
---
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width">
<title>{title}</title>
</head>
<body>
<main>
<header>
<div>
<h1>ajcwebdev-astro</h1>
</div>
<p>Hello! This is an example Astro project by Anthony Campolo (ajcwebdev).</p>
</header>
</main>
<footer>
<h3>Find me on the internet:</h3>
<ul>
<li><a href="https://ajcwebdev.com">Blog</a></li>
<li><a href="https://github.com/ajcwebdev">GitHub</a></li>
<li><a href="https://twitter.com/ajcwebdev">Twitter</a></li>
</ul>
</footer>
</body>
</html>
Start Development Server
yarn dev
Open localhost:3000 to see the home page.
Add Styling
I'll include Water.css in the head
of index.html
for some nice looking CSS defaults.
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/water.css@2/out/water.css">
<title>{title}</title>
</head>
Add Components
We'll create a directory called components
inside src
to hold any Astro/React/Vue/Svelte/Preact components. Then we will create three extra directories that will hold .astro
, .jsx
, and .svelte
files for Markdown, React, and Svelte components respectively.
Create a Markdown Component
The first example will use Markdown and render completely statically. Astro includes a built in Markdown
component that can be imported into any .md
file.
mkdir -p src/components/markdown
touch src/components/markdown/HelloMarkdown.astro
Import the Markdown
component from astro/components
and write some Markdown.
---
// src/components/markdown/HelloMarkdown.astro
import { Markdown } from 'astro/components'
---
<article>
<section>
<h2>Markdown</h2>
<Markdown>
### This is an h3 with Markdown
*Pretty* **cool**, ***right***?
</Markdown>
</section>
</article>
Return to index.astro
and import HelloMarkdown
from '../components/markdown/HelloMarkdown.astro'
. Place <HelloMarkdown />
inside the main
tags.
---
// src/pages/index.astro
import HelloMarkdown from '../components/markdown/HelloMarkdown.astro'
let title = 'ajcwebdev-astro'
---
<html lang="en">
<head>...</head>
<body>
<main>
<header>...</header>
</main>
<section>
<HelloMarkdown />
</section>
<footer>...</footer>
</body>
</html>
Create a React Component
To configure Astro, add an astro.config.mjs
file and install the necessary React dependencies by running the following command:
yarn astro add react
This installs @astrojs/react
, react-dom@^18.0.0
, and react@^18.0.0
. It also adds the following code to astro.config.mjs
to enable the React renderer and provide support for React JSX components.
// astro.config.mjs
import { defineConfig } from 'astro/config'
import react from "@astrojs/react"
export default defineConfig({
integrations: [react()]
})
We'll create a react
directory with a HelloReact.jsx
component inside.
mkdir src/components/react
touch src/components/react/HelloReact.jsx
It's a React component so you're contractually obligated to make it a counter with useState
that is triggered with an onClick
event handler on a <button>
.
// src/components/react/HelloReact.jsx
import { useState } from 'react'
export default function HelloReact({ children, count: initialCount }) {
const [count, setCount] = useState(initialCount)
const add = () => setCount((i) => i + 1)
const subtract = () => setCount((i) => i - 1)
return (
<>
<h2>{children}</h2>
<div style={{display:'flex'}}>
<button onClick={subtract}>-</button>
<pre>{count}</pre>
<button onClick={add}>+</button>
</div>
</>
)
}
Importing the HelloReact
component is much like the HelloMarkdown
component. However, this time we're including someProps
in the front matter to set the initial count
to 0
.
---
// src/pages/index.astro
import HelloMarkdown from '../components/markdown/HelloMarkdown.astro'
import HelloReact from '../components/react/HelloReact.jsx'
const someProps = {
count: 0,
}
let title = 'ajcwebdev-astro'
---
<html lang="en">
<head>...</head>
<body>
<main>
<header>...</header>
<HelloReact {...someProps} client:visible>
React
</HelloReact>
</main>
<section>
<HelloMarkdown />
</section>
<footer>...</footer>
</body>
</html>
We also include client:visible
to hydrate the component as soon as the element enters the viewport.
Create a Svelte Component
Add svelte()
to integrations
in astro.config.mjs
to enable the Svelte renderer and provide support for Svelte components.
yarn astro add svelte
This also installs @astrojs/svelte
and svelte@^3.46.4
.
// astro.config.mjs
import { defineConfig } from 'astro/config'
import react from "@astrojs/react"
import svelte from "@astrojs/svelte"
export default defineConfig({
integrations: [react(), svelte()]
})
As with React, create a svelte
directory and HelloSvelte.svelte
file.
mkdir src/components/svelte
touch src/components/svelte/HelloSvelte.svelte
Our Svelte component will contain the same functionality as our React component.
<!-- src/components/svelte/HelloSvelte.svelte -->
<script>
let count = 0
function add() {
count += 1
}
function subtract() {
count -= 1
}
</script>
<h2><slot /></h2>
<div>
<button on:click={subtract}>-</button>
<pre>{ count }</pre>
<button on:click={add}>+</button>
</div>
<style>
div {
display: flex;
}
</style>
Import HelloSvelte
and set it to client:visible
.
---
// src/pages/index.astro
import HelloMarkdown from '../components/markdown/HelloMarkdown.astro'
import HelloReact from '../components/react/HelloReact.jsx'
import HelloSvelte from '../components/svelte/HelloSvelte.svelte'
const someProps = {
count: 0,
}
let title = 'ajcwebdev-astro'
---
<html lang="en">
<head>...</head>
<body>
<main>
<header>...</header>
<HelloReact {...someProps} client:visible>
React
</HelloReact>
<HelloSvelte client:visible>
Svelte
</HelloSvelte>
</main>
<section>
<HelloMarkdown />
</section>
<footer>...</footer>
</body>
</html>
Create a Vue Component
Add vue()
to integrations
in astro.config.mjs
to enable the Vue renderer.
yarn astro add vue
This also install @astrojs/vue
and vue@^3.2.30
.
// astro.config.mjs
import { defineConfig } from 'astro/config'
import react from "@astrojs/react"
import svelte from "@astrojs/svelte"
import vue from "@astrojs/vue"
export default defineConfig({
integrations: [react(), svelte(), vue()]
})
You know the drill.
mkdir src/components/vue
touch src/components/vue/HelloVue.vue
Our Vue component will contain the same functionality as our React and Svelte components.
<!-- src/components/vue/HelloVue.vue -->
<template>
<h2><slot /></h2>
<div>
<button @click="subtract()">-</button>
<pre>{{ count }}</pre>
<button @click="add()">+</button>
</div>
</template>
<script>
import { ref } from 'vue'
export default {
setup() {
const count = ref(0)
const add = () => (count.value = count.value + 1)
const subtract = () => (count.value = count.value - 1)
return {
count, add, subtract,
}
},
}
</script>
<style scoped>
div {
display: flex;
}
</style>
Import HelloVue
and set it to client:visible
.
---
// src/pages/index.astro
import HelloMarkdown from '../components/markdown/HelloMarkdown.astro'
import HelloReact from '../components/react/HelloReact.jsx'
import HelloSvelte from '../components/svelte/HelloSvelte.svelte'
import HelloVue from '../components/vue/HelloVue.vue'
const someProps = {
count: 0,
}
let title = 'ajcwebdev-astro'
---
<html lang="en">
<head>...</head>
<body>
<main>
<header>...</header>
<HelloReact {...someProps} client:visible>
React
</HelloReact>
<HelloSvelte client:visible>
Svelte
</HelloSvelte>
<HelloVue client:visible>
Vue
</HelloVue>
</main>
<section>
<HelloMarkdown />
</section>
<footer>...</footer>
</body>
</html>
Create a GraphQL Data Fetching Component
mkdir src/components/graphql
touch src/components/graphql/HelloGraphQL.astro src/pages/graphql.astro
---
// src/components/graphql/HelloGraphQL.astro
const res = await fetch('https://rickandmortyapi.com/graphql', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify({
query: `{
characters {
results {
name
}
}
}`
})
})
const { data } = await res.json()
const { characters } = data
---
<h2>Rick and Morty GraphQL API</h2>
<ul>
{characters.results.map(({ name }) => (
<li>{name}</li>
))}
</ul>
Import HelloGraphQL
.
---
// src/pages/graphql.astro
import HelloGraphQL from '../components/graphql/HelloGraphQL.astro'
let title = 'GraphQL'
---
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width">
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/water.css@2/out/water.css">
<title>{title}</title>
</head>
<body>
<main>
<HelloGraphQL />
</main>
</body>
</html>
Deploy to Netlify
The Astro docs contain over a dozen different deployment options. We will deploy our project to Netlify. Create a netlify.toml
file for our build configuration.
touch netlify.toml
Add yarn build
for the build command and dist
for the publish directory.
[build]
command = "yarn build"
publish = "dist"
Here is our final project structure.
/
├── public
├── src
│ ├── components
│ │ ├── graphql
│ │ │ └── HelloGraphQL.astro
│ │ ├── markdown
│ │ │ └── HelloMarkdown.astro
│ │ ├── react
│ │ │ └── HelloReact.jsx
│ │ ├── svelte
│ │ │ └── HelloSvelte.svelte
│ │ └── vue
│ │ └── HelloVue.vue
│ └── pages
│ ├── graphql.astro
│ └── index.astro
├── .gitignore
├── astro.config.mjs
├── netlify.toml
└── package.json
Create a GitHub Repository
Initialize a git repo and push to a GitHub repository.
git init
git add .
git commit -m "svuereactroQL"
gh repo create ajcwebdev-astro --public --push \
--source=. \
--description="Example Astro project with Markdown, React, Svelte, and Vue" \
--remote=upstream
Connect GitHub Repository to Netlify
Connect your GitHub repository to Netlify.
Go to "Site settings," to give yourself a custom domain name.
Open ajcwebdev-astro.netlify.app to see the deployed site.