mirror of
https://github.com/withastro/astro.git
synced 2024-12-23 21:53:55 -05:00
198 lines
8.3 KiB
Markdown
198 lines
8.3 KiB
Markdown
# 🪄 Renderers
|
||
|
||
Astro is designed to support your favorite UI frameworks. [React](https://npm.im/@astrojs/renderer-react), [Svelte](https://npm.im/@astrojs/renderer-svelte), [Vue](https://npm.im/@astrojs/renderer-vue), and [Preact](https://npm.im/@astrojs/renderer-preact) are all built-in to Astro and supported out of the box. No configuration is needed to enable these.
|
||
|
||
Internally, each framework is supported via a framework **renderer.** A renderer is a type of Astro plugin that adds support for a framework. Some are built-in, but you can also provide your own third-party renderers to add Astro support for new frameworks.
|
||
|
||
## What is a renderer?
|
||
|
||
A renderer is an NPM package that has two responsiblities:
|
||
|
||
1. _render a component to a static string of HTML_ at build time
|
||
2. _rehydrate that HTML to create an interactive component_ on the client.
|
||
|
||
Take a look at any one of Astro's built-in [`renderers`](https://github.com/snowpackjs/astro/tree/main/packages/renderers) to see this in action. We'll go into more detail in the following sections.
|
||
|
||
## Add a renderer to Astro
|
||
|
||
Astro enables a few popular framework renderers by default. If you want to add a new renderer to your project, you first need to set the built-in renderers that you care about.
|
||
|
||
```js
|
||
// astro.config.js
|
||
export default {
|
||
renderers: [
|
||
// Add the framework renderers that you want to enable for your project.
|
||
// If you set an empty array here, no UI frameworks will work.
|
||
// '@astrojs/renderer-svelte',
|
||
// '@astrojs/renderer-vue',
|
||
// '@astrojs/renderer-react',
|
||
// '@astrojs/renderer-preact',
|
||
],
|
||
};
|
||
```
|
||
|
||
To add a new custom renderer, install the npm package dependency in your project and then update the `renderers` array to include it:
|
||
|
||
```js
|
||
// astro.config.js
|
||
export default {
|
||
renderers: ['my-custom-renderer', '@astrojs/renderer-svelte', '@astrojs/renderer-vue', '@astrojs/renderer-react', '@astrojs/renderer-preact'],
|
||
};
|
||
```
|
||
|
||
#### Managing Framework Versions
|
||
|
||
In Astro, the renderer plugin defines which version of your framework to use with Astro. This should be set to as wide of a range as possible, but often will be pinned to a specific major version:
|
||
|
||
- `@astrojs/renderer-vue`: `"vue": "^3.0.0"`
|
||
- `@astrojs/renderer-react`: `"react": "^17.0.0"`
|
||
- See all: https://github.com/snowpackjs/astro/tree/main/packages/renderers
|
||
|
||
This is required because the renderer itself also uses these packages and requires a specific API to work. For example, If the user updated from Vue 2 to Vue 3 (or vice versa) then the renderer itself would break since the `vue` package would have changed.
|
||
|
||
**What if I want to use a beta framework (ex: react@next)?** Check to see if the renderer has a `@next` version that you could manually install and use. If one doesn't exist, feel free to request it: https://github.com/snowpackjs/astro/issues/new/choose
|
||
|
||
**What if I need to override the framework version in my project?** You can use the "resolutions" feature of many npm package managers to override or pin the framework version for your entire project. Just be sure to select a version that is compatible with your renderer:
|
||
|
||
- **yarn:** https://classic.yarnpkg.com/en/docs/selective-version-resolutions/
|
||
- **pnpm:** https://pnpm.io/package_json#pnpmoverrides
|
||
- **npm:** see https://stackoverflow.com/questions/15806152/how-do-i-override-nested-npm-dependency-versions
|
||
|
||
## Building Your Own Renderer
|
||
|
||
> **Building a renderer?** We'd love for you to contribute renderers for popular frameworks back to the Astro repo. Feel free to open an issue or pull request to discuss.
|
||
|
||
A simple renderer only needs a few files:
|
||
|
||
```
|
||
/my-custom-renderer/
|
||
├── package.json
|
||
├── index.js
|
||
├── server.js
|
||
└── client.js
|
||
```
|
||
|
||
### Package Manifest (`package.json`)
|
||
|
||
A renderer should include any framework dependencies as package dependencies. For example, `@astrojs/renderer-react` includes `react` & `react-dom` as dependencies in the `package.json` manifest.
|
||
|
||
```js
|
||
// package.json
|
||
"name": "@astrojs/renderer-react",
|
||
"dependencies": {
|
||
"react": "^17.0.0",
|
||
"react-dom": "^17.0.0"
|
||
}
|
||
```
|
||
|
||
This means that Astro users don't need to install the UI framework packages themselves. The renderer is the only package that your users will need to install.
|
||
|
||
### Renderer Entrypoint (`index.js`)
|
||
|
||
The main entrypoint of a renderer is a simple JS file which exports a manifest for the renderer. The required values are `name`, `server`, and `client`.
|
||
|
||
Additionally, this entrypoint can define a [Snowpack plugin](https://www.snowpack.dev/guides/plugins) that should be used to load non-JavaScript files.
|
||
|
||
```js
|
||
export default {
|
||
name: '@astrojs/renderer-xxx', // the renderer name
|
||
client: './client.js', // relative path to the client entrypoint
|
||
server: './server.js', // relative path to the server entrypoint
|
||
snowpackPlugin: '@snowpack/plugin-xxx', // optional, the name of a snowpack plugin to inject
|
||
snowpackPluginOptions: { example: true }, // optional, any options to be forwarded to the snowpack plugin
|
||
};
|
||
```
|
||
|
||
### Server Entrypoint (`server.js`)
|
||
|
||
The server entrypoint of a renderer is responsible for checking if a component should use this renderer, and if so, how that component should be rendered to a string of static HTML.
|
||
|
||
```js
|
||
export default {
|
||
// should Component use this renderer?
|
||
check(Component, props, childHTML) {},
|
||
// Component => string of static HTML
|
||
renderToStaticMarkup(Component, props, childHTML) {},
|
||
};
|
||
```
|
||
|
||
#### `check`
|
||
|
||
`check` is a function that determines whether a Component should be "claimed" by this renderer.
|
||
|
||
In it's simplest form, it can check for the existence of a flag on Object-based components.
|
||
|
||
```js
|
||
function check(Component) {
|
||
return Component.isMyFrameworkComponent;
|
||
}
|
||
```
|
||
|
||
In more complex scenarios, like when a Component is a `Function` without any flags, you may need to use `try/catch` to attempt a full render. This result is cached so that it only runs once per-component.
|
||
|
||
```js
|
||
function check(Component, props, childHTML) {
|
||
try {
|
||
const { html } = renderToStaticMarkup(Component, props, childHTML);
|
||
return Boolean(html);
|
||
} catch (e) {}
|
||
return false;
|
||
}
|
||
```
|
||
|
||
#### `renderToStaticMarkup`
|
||
|
||
`renderToStaticMarkup` is a function that renders a Component to a static string of HTML. There's usually a method exported by frameworks named something like `renderToString`.
|
||
|
||
```js
|
||
import { renderToString } from 'xxx';
|
||
|
||
function renderToStaticMarkup(Component, props, childHTML) {
|
||
const html = renderToString(h(Component, { ...props, innerHTML: childHTML }));
|
||
return { html };
|
||
}
|
||
```
|
||
|
||
Note that `childHTML` is an HTML string representing this component's children. If your framework does not support rendering HTML directly, you are welcome to use a wrapper component. By convention, Astro uses the `astro-fragment` custom element to inject `childHTML` into. Your renderer should use that, too.
|
||
|
||
```js
|
||
import { h, renderToString } from 'xxx';
|
||
|
||
const Wrapper = ({ value }) => h('astro-fragment', { dangerouslySetInnerHTML: { __html: value } });
|
||
|
||
function renderToStaticMarkup(Component, props, childHTML) {
|
||
const html = renderToString(h(Component, props, h(Wrapper, { value: childHTML })));
|
||
return { html };
|
||
}
|
||
```
|
||
|
||
### Client Entrypoint (`client.js`)
|
||
|
||
The client entrypoint of a renderer is responsible for rehydrating static HTML (the result of `renderToStaticMarkup`) back into a fully interactive component. Its `default` export should be a `function` which accepts the host element of the Component, an `astro-root` custom element.
|
||
|
||
> If your framework supports non-destructive component hydration (as opposed to a destructive `render` method), be sure to use that! Following your framework's Server Side Rendering (SSR) guide should point you in the right direction.
|
||
|
||
```js
|
||
import { hydrate } from 'xxx';
|
||
|
||
export default (element) => {
|
||
return (Component, props, childHTML) => {
|
||
hydrate(h(Component, { ...props, innerHTML: childHTML }), element);
|
||
};
|
||
};
|
||
```
|
||
|
||
Note that `childHTML` is an HTML string representing this component's children. If your framework does not support rendering HTML directly, you should use the same wrapper component you used for the server entrypoint.
|
||
|
||
```js
|
||
import { h, hydrate } from 'xxx';
|
||
import SharedWrapper from './SharedWrapper.js';
|
||
|
||
export default (element) => {
|
||
return (Component, props, childHTML) => {
|
||
hydrate(h(Component, props, h(SharedWrapper, { value: childHTML })), element);
|
||
};
|
||
};
|
||
```
|
||
|
||
[astro-config]: ./config.md
|