astro/README.md
Nate Moore 188541260a
chore: remove github banner, add to banner to README (#108)
Co-authored-by: Nate Moore <nate@skypack.dev>
2021-04-16 12:51:30 -05:00

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![Astro](./assets/social/banner.png)
**Astro** is a next-generation static-site generator with partial hydration. Use your favorite JS framework and ship bare-minimum JS (or none at all!).
## 🔧 Setup
```bash
# currently hidden during private beta, please don't share :)
npm install astro@shhhhh
# NOTE: There is currently a bug in Snowpack that prevents you
# from using astro outside of the monorepo setup that we have here.
# For now, do all development inside the `examples/` directory for this repo.
```
## 🧞 Development
Add a `dev` npm script to your `/package.json` file:
```json
{
"scripts": {
"dev": "astro dev ."
}
}
```
Then run:
```
npm run dev
```
### ⚙️ Configuration
To configure Astro, add a `astro.config.mjs` file in the root of your project. All settings are optional. Here are the defaults:
```js
export default {
/** Where to resolve all URLs relative to. Useful if you have a monorepo project. */
projectRoot: '.',
/** Path to Astro components, pages, and data */
astroRoot: './astro',
/** When running `astro build`, path to final static output */
dist: './_site',
/** A folder of static files Astro will copy to the root. Useful for favicons, images, and other files that dont need processing. */
public: './public',
/** Extension-specific handlings */
extensions: {
/** Set this to "preact" or "react" to determine what *.jsx files should load */
'.jsx': 'react',
},
/** Your public domain, e.g.: https://my-site.dev/ */
site: '',
};
```
### 💧 Partial Hydration
By default, Astro outputs zero client-side JS. If you'd like to include an interactive component in the client output, you may use any of the following techniques.
- `<MyComponent />` will render an HTML-only version of `MyComponent` (default)
- `<MyComponent:load />` will render `MyComponent` on page load
- `<MyComponent:idle />` will use [requestIdleCallback()][request-idle-cb] to render `MyComponent` as soon as main thread is free
- `<MyComponent:visible />` will use an [IntersectionObserver][intersection-observer] to render `MyComponent` when the element enters the viewport
### ⚛️ State Management
Frontend state management depends on your framework of choice. Below is a list of popular frontend state management libraries, and their current support with Astro.
Our goal is to support all popular state management libraries, as long as there is no technical reason that we cannot.
- **React/Preact**
- [ ] **Redux: Partial Support** (Note: You can access a Redux store directly, but full `react-redux` support requires the ability to set a custom `<Provider>` wrapper to every component island. Planned.)
- [x] **Recoil: Full Support**
- **Svelte**
- [x] **Svelte Stores: Full Support**
- **Vue:**
- [ ] **Vuex: Partial Support** (Note: You can access a vuex store directly, but full `vuex` support requires the ability to set a custom `vue.use(store)` call to every component island. Planned.)
_Are we missing your favorite state management library? Add it to the list above in a PR (or create an issue)!_
### 💅 Styling
If youve used [Svelte][svelte]s styles before, Astro works almost the same way. In any `.astro` file, start writing styles in a `<style>` tag like so:
```html
<style>
.scoped {
font-weight: bold;
}
</style>
<div class="scoped">Im a scoped style</div>
```
#### 👓 Sass
Astro also supports [Sass][sass] out-of-the-box; no configuration needed:
```html
<style lang="scss">
@use "../tokens" as *;
.title {
color: $color.gray;
}
</style>
<h1 class="title">Title</h1>
```
Supports:
- `lang="scss"`: load as the `.scss` extension
- `lang="sass"`: load as the `.sass` extension (no brackets; indent-style)
#### 🦊 Autoprefixer
We also automatically add browser prefixes using [Autoprefixer][autoprefixer]. By default, Astro loads the default values, but you may also specify your own by placing a [Browserslist][browserslist] file in your project root.
## 🥾 Guides
#### 🍱 Collections (beta)
By default, any Astro component can fetch data from any API or local `*.md` files. But what if you had a blog you wanted to paginate? What if you wanted to generate dynamic URLs based on metadata (e.g. `/tag/[tag]/`)? Or do both together? Astro Collections are a way to do all of that. Its perfect for generating blog-like content, or scaffolding out dynamic URLs from your data.
First, decide on a URL schema. For our example, perhaps you want all your paginated posts at `/posts/1`, `/posts/2`, etc. But in addition, you also wanted `/tag/[tag]` and `/year/[year]` collections where posts are filtered by tag or year.
Next, for each “owner” of a URL tree, create a `/astro/pages/$[collection].astro` file. So in our example, wed need 3:
```
└── astro/
└── pages/
├── $posts.astro -> /posts/1, /posts/2, …
├── $tag.astro -> /tag/[tag]/1, /tag/[tag]/2, …
└── $year.astro -> /year/[year]/1, /year/[year]/2, …
```
Lastly, in each `$[collection].astro` file, add 2 things:
```js
export let collection: any;
```
```js
export async function createCollection() {
return {
async data() {
// return data here to load (well cover how later)
},
};
}
```
These are important so your data is exposed to the page as a prop, and also Astro has everything it needs to gather your data and generate the proper routes. How it does this is more clear if we walk through a practical example.
#### Example 1: Simple pagination
Assume we have Markdown files that have `title`, `tag`, and `date` in their frontmatter, like so:
```md
---
title: My Blog Post
tag: javascript
date: 2021-03-01 09:34:00
---
# My Blog post
```
Its important to know that these could be anything! Theres no restrictions around what can go in your frontmatter, but these will explain values we see later. Assume nothing is “special“ or reserved; we named everything.
Also, assume we want the following final routes:
- Individual blog posts live at `/post/[slug]`.
- The paginated blog posts live at `/posts/1` for page 1, `/posts/2` for page 2, etc.
- We also want to add `/tag/[tag]/1` for tagged posts, page 1, or `/year/[year]/1` for posts by year. Well add these at the end.
Lets start with paginated posts. Since we want `/posts/` to be the root, well create a file at `/astro/pages/$posts.astro` (the `$` indicates that this is a multi-route page):
```html
// /astro/pages/$posts.astro
---
import Pagination from '../components/Pagination.astro';
import PostPreview from '../components/PostPreview.astro';
export let collection: any;
export async function createCollection() {
const allPosts = Astro.fetchContent('./post/*.md'); // load data that already lives at `/post/[slug]`
allPosts.sort((a, b) => new Date(b.date) - new Date(a.date)); // sort newest -> oldest (we got "date" from frontmatter!)
// (load more data here, if needed)
return {
async data() {
return allPosts;
},
pageSize: 10, // how many we want to show per-page (default: 25)
};
}
---
<html lang="en">
<head>
<meta charset="UTF-8" />
<title>Blog Posts: page {collection.page.current}</title>
<link rel="canonical" href={collection.url.current} />
<link rel="prev" href={collection.url.prev} />
<link rel="next" href={collection.url.next} />
</head>
<body>
<main>
<h5>Results {collection.start + 1}{collection.start + 1 + collection.page.size} of {collection.total}</h6>
{collection.data.map((post) => (
<PostPreview post={post} />
)}
</main>
<footer>
<Pagination
currentPage={collection.page.current}
totalPages={collection.page.last}
prevURL={collection.url.prev}
nextURL={collection.url.next}
/>
</footer>
</body>
</html>
```
Lets walk through some of the key parts:
- `export let collection`: this is important because it exposes a prop to the page for Astro to return with all your data loaded. ⚠️ **It must be named `collection`**.
- `export async function createCollection()`: this is also required, **and must be named this exactly.** This is an async function that lets you load data from anywhere (even a remote API!). At the end, you must return an object with `{ data: yourData }`. There are other options such as `pageSize` well cover later.
- `{collection.data.map((post) => (…`: this lets us iterate over all the markdown posts. This will take the shape of whatever you loaded in `createCollection()`. It will always be an array.
- `{collection.page.current}`: this, and other properties, simply return more info such as what page a user is on, what the URL is, etc. etc.
It should be noted that the above example shows `<PostPreview />` and `<Pagination />` components. Pretend those are custom components that you made to display the post data, and the pagination navigation. Theres nothing special about them; only consider those examples of how youd use collection data to display everything the way youd like.
#### Example 2: Advanced filtering & pagination
In our earlier example, we covered simple pagination for `/posts/1`, but wed still like to make `/tag/[tag]/1` and `/year/[year]/1`. To do that, well create 2 more collections: `/astro/pages/$tag.astro` and `astro/pages/$year.astro`. Assume that the markup is the same, but weve expanded the `createCollection()` function with more data.
```diff
// /astro/pages/$tag.astro
---
import Pagination from '../components/Pagination.astro';
import PostPreview from '../components/PostPreview.astro';
export let collection: any;
export async function createCollection() {
const allPosts = Astro.fetchContent('./post/*.md');
allPosts.sort((a, b) => new Date(b.date) - new Date(a.date));
+ const allTags = [...new Set(allPosts.map((post) => post.tags).flat())]; // gather all unique tags (we got "tag" from frontmatter!)
+ allTags.sort((a, b) => a.localeCompare(b)); // sort tags A -> Z
+ const routes = allTags.map((tag) => ({ tag })); // this is where we set { params: { tag } }
return {
- async data() {
- return allPosts;
+ async data({ params }) {
+ return allPosts.filter((post) => post.tag === params.tag); // filter post by "date" frontmatter, from params (we get `{ params }` from the routes array above)
},
pageSize: 10,
+ routes,
+ permalink: ({ params }) => `/tag/${params.tag}/` // important! the root must match (/tag/[tag] -> $tag.astro)
};
}
---
```
Some important concepts here:
- `routes = allTags.map((tag) => ({ tag }))`: Astro handles pagination for you automatically. But when it needs to generate multiple routes, this is where you tell Astro about all the possible routes. This way, when you run `astro build`, your static build isnt missing any pages.
- `permalink: ({ params }) => `/tag/${params.tag}/`: this is where you tell Astro what the generated URL should be. Note that while you have control over this, the root of this must match the filename (its best **NOT** to use `/pages/$tag.astro`to generate`/year/$year.astro`; that should live at `/pages/$year.astro` as a separate file).
- `allPosts.filter((post) => post.tag === params.tag)`: we arent returning all posts here; were only returning posts with a matching tag. _What tag,_ you ask? The `routes` array has `[{ tag: 'javascript' }, { tag: '…`, and all the routes we need to gather. So we first need to query everything, but only return the `.filter()`ed posts at the very end.
Other things of note is that we are sorting like before, but we filter by the frontmatter `tag` property, and return those at URLs.
These are still paginated, too! But since there are other conditions applied, they live at a different URL.
Lastly, what about `/year/*`? Well hopefully you can figure that out from here. It follows the exact same pattern, except using `post.date` frontmatter. Youll grab the year from that date string, and sort probably newest to oldest rather than alphabetical. Youll also change `params.tag` to `params.year` (or whatever you name it), but otherwise most everything else should be the same.
#### Tips
- Having to load different collections in different `$[collection].astro` files might seem like a pain at first, until you remember **you can create reusable components!** Treat `/pages/*.astro` files as your one-off routing & data fetching logic, and treat `/components/*.astro` as your reusable markup. If you find yourself duplicating things too much, you can probably use a component instead!
- Stay true to `/pages/$[collection].astro` naming. If you have an `/all-posts/*` route, then use `/pages/$all-posts.astro` to manage that. Dont try and trick `permalink` to generate too many URL trees; itll only result in pages being missed when it comes time to build.
- Need to load local markdown? Try [`Astro.fetchContent()`][fetch-content]
- Need to load remote data from an API? Simply `fetch()` to make it happen!
#### 🍃 Tailwind
Astro can be configured to use [Tailwind][tailwind] easily! Install the dependencies:
```
npm install --save-dev tailwindcss
```
And also create a `tailwind.config.js` in your project root:
```js
// tailwind.config.js
module.exports = {
mode: 'jit',
purge: ['./public/**/*.html', './astro/**/*.{astro,js,jsx,ts,tsx,vue}'],
// more options here
};
```
Then add [Tailwind utilities][tailwind-utilities] to any Astro component that needs it:
```html
<style>
@tailwind base;
@tailwind components;
@tailwind utilities;
</style>
```
You should see Tailwind styles compile successfully in Astro.
💁 **Tip**: to reduce duplication, try loading `@tailwind base` from a parent page (`./pages/*.astro`) instead of the component itself.
## 🚀 Build & Deployment
Add a `build` npm script to your `/package.json` file:
```json
{
"scripts": {
"dev": "astro dev .",
"build": "astro build ."
}
}
```
Then run:
```
npm run build
```
Now upload the contents of `/_site_` to your favorite static site host.
## 📚 API
### `Astro` global
The `Astro` global is available in all contexts in `.astro` files. It has the following functions:
#### `config`
`Astro.config` returns an object with the following properties:
| Name | Type | Description |
| :----- | :------- | :--------------------------------------------------------------------------------------------------------- |
| `site` | `string` | Your websites public root domain. Set it with `site: "https://mysite.com"` in your [Astro config][config] |
#### `fetchContent()`
`Astro.fetchContent()` is a way to load local `*.md` files into your static site setup. You can either use this on its own, or within [Astro Collections][collections].
```
// ./astro/components/my-component.astro
---
const data = Astro.fetchContent('../pages/post/*.md'); // returns an array of posts that live at ./astro/pages/post/*.md
---
<div>
{data.slice(0, 3).map((post) => (
<article>
<h1>{post.title}</h1>
<p>{post.description}</p>
<a href={post.url}>Read more</a>
</article>
))}
</div>
```
`.fetchContent()` only takes one parameter: a relative URL glob of which local files youd like to import. Currently only `*.md` files are supported. Its synchronous, and returns an array of items of type:
```
{
url: string; // the URL of this item (if its in pages/)
content: string; // the HTML of this item
// frontmatter data expanded here
}[];
```
[autoprefixer]: https://github.com/postcss/autoprefixer
[browserslist]: https://github.com/browserslist/browserslist
[collections]: #-collections-beta
[config]: #%EF%B8%8F-configuration
[fetch-content]: #fetchContent--
[intersection-observer]: https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API
[request-idle-cb]: https://developer.mozilla.org/en-US/docs/Web/API/Window/requestIdleCallback
[sass]: https://sass-lang.com/
[svelte]: https://svelte.dev
[tailwind]: https://tailwindcss.com
[tailwind-utilities]: https://tailwindcss.com/docs/adding-new-utilities#using-css