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2 | 2 |
|
3 | 3 | This **[Astro integration][astro-integration]** enables server-side rendering and client-side hydration for your [Lit](https://lit.dev/) custom elements. |
4 | 4 |
|
5 | | -## Installation |
| 5 | +## Documentation |
6 | 6 |
|
7 | | -There are two ways to add integrations to your project. Let's try the most convenient option first! |
| 7 | +Read the [`@astrojs/lit` docs][docs] |
8 | 8 |
|
9 | | -### `astro add` command |
| 9 | +## Support |
10 | 10 |
|
11 | | -Astro includes a CLI tool for adding first party integrations: `astro add`. This command will: |
| 11 | +- Get help in the [Astro Discord][discord]. Post questions in our `#support` forum, or visit our dedicated `#dev` channel to discuss current development and more! |
12 | 12 |
|
13 | | -1. (Optionally) Install all necessary dependencies and peer dependencies |
14 | | -2. (Also optionally) Update your `astro.config.*` file to apply this integration |
| 13 | +- Check our [Astro Integration Documentation][astro-integration] for more on integrations. |
15 | 14 |
|
16 | | -To install `@astrojs/lit`, run the following from your project directory and follow the prompts: |
| 15 | +- Submit bug reports and feature requests as [GitHub issues][issues]. |
17 | 16 |
|
18 | | -```sh |
19 | | -# Using NPM |
20 | | -npx astro add lit |
21 | | -# Using Yarn |
22 | | -yarn astro add lit |
23 | | -# Using PNPM |
24 | | -pnpm astro add lit |
25 | | -``` |
26 | | - |
27 | | -If you run into any issues, [feel free to report them to us on GitHub](https://github.com/withastro/astro/issues) and try the manual installation steps below. |
28 | | - |
29 | | -### Install dependencies manually |
30 | | - |
31 | | -First, install the `@astrojs/lit` integration like so: |
32 | | - |
33 | | -```sh |
34 | | -npm install @astrojs/lit |
35 | | -``` |
36 | | - |
37 | | -Most package managers will install associated peer dependencies as well. Still, if you see a "Cannot find package 'lit'" (or similar) warning when you start up Astro, you'll need to install `lit` and `@webcomponents/template-shadowroot`: |
38 | | - |
39 | | -```sh |
40 | | -npm install lit @webcomponents/template-shadowroot |
41 | | -``` |
42 | | - |
43 | | -Now, apply this integration to your `astro.config.*` file using the `integrations` property: |
44 | | - |
45 | | -```diff lang="js" "lit()" |
46 | | - // astro.config.mjs |
47 | | - import { defineConfig } from 'astro/config'; |
48 | | -+ import lit from '@astrojs/lit'; |
49 | | - |
50 | | - export default defineConfig({ |
51 | | - // ... |
52 | | - integrations: [lit()], |
53 | | - // ^^^^^ |
54 | | - }); |
55 | | -``` |
56 | | - |
57 | | -## Getting started |
58 | | - |
59 | | -To use your first Lit component in Astro, head to our [UI framework documentation][astro-ui-frameworks]. This explains: |
60 | | - |
61 | | -- 📦 how framework components are loaded, |
62 | | -- 💧 client-side hydration options, and |
63 | | -- 🤝 opportunities to mix and nest frameworks together |
64 | | - |
65 | | -Writing and importing a Lit component in Astro looks like this: |
66 | | - |
67 | | -```js |
68 | | -// src/components/my-element.js |
69 | | -import { LitElement, html } from 'lit'; |
70 | | - |
71 | | -export class MyElement extends LitElement { |
72 | | - render() { |
73 | | - return html` <p>Hello world! From my-element</p> `; |
74 | | - } |
75 | | -} |
76 | | - |
77 | | -customElements.define('my-element', MyElement); |
78 | | -``` |
79 | | - |
80 | | -Now, the component is ready to be imported via the Astro frontmatter: |
81 | | - |
82 | | -```astro |
83 | | ---- |
84 | | -// src/pages/index.astro |
85 | | -import { MyElement } from '../components/my-element.js'; |
86 | | ---- |
87 | | -
|
88 | | -<MyElement /> |
89 | | -``` |
90 | | - |
91 | | -> Note that Lit requires browser globals such as `HTMLElement` and `customElements` to be present. For this reason the Lit renderer shims the server with these globals so Lit can run. You _might_ run into libraries that work incorrectly because of this. |
92 | | -
|
93 | | -### Polyfills & Hydration |
94 | | - |
95 | | -The renderer automatically handles adding appropriate polyfills for support in browsers that don't have Declarative Shadow DOM. The polyfill is about _1.5kB_. If the browser does support Declarative Shadow DOM then less than 250 bytes are loaded (to feature detect support). |
96 | | - |
97 | | -Hydration is also handled automatically. You can use the same hydration directives such as `client:load`, `client:idle` and `client:visible` as you can with other libraries that Astro supports. |
98 | | - |
99 | | -```astro |
100 | | ---- |
101 | | -import { MyElement } from '../components/my-element.js'; |
102 | | ---- |
103 | | -
|
104 | | -<MyElement client:visible /> |
105 | | -``` |
106 | | - |
107 | | -The above will only load the element's JavaScript when the user has scrolled it into view. Since it is server rendered they will not see any jank; it will load and hydrate transparently. |
108 | | - |
109 | | -## Troubleshooting |
110 | | - |
111 | | -For help, check out the `#support` channel on [Discord](https://astro.build/chat). Our friendly Support Squad members are here to help! |
112 | | - |
113 | | -You can also check our [Astro Integration Documentation][astro-integration] for more on integrations. |
114 | | - |
115 | | -Common issues are listed below: |
116 | | - |
117 | | -### Browser globals |
118 | | - |
119 | | -The Lit integration's SSR works by adding a few browser global properties to the global environment. Some of the properties it adds includes `window`, `document`, and `location`. |
120 | | - |
121 | | -These globals _can_ interfere with other libraries that might use the existence of these variables to detect that they are running in the browser, when they are actually running in the server. This can cause bugs with these libraries. |
122 | | - |
123 | | -Because of this, the Lit integration might not be compatible with these types of libraries. One thing that can help is changing the order of integrations when Lit is interfering with other integrations: |
124 | | - |
125 | | -```diff lang="js" |
126 | | - // astro.config.mjs |
127 | | - import { defineConfig } from 'astro/config'; |
128 | | - import vue from '@astrojs/vue'; |
129 | | - import lit from '@astrojs/lit'; |
130 | | - |
131 | | - export default defineConfig({ |
132 | | -- integrations: [vue(), lit()] |
133 | | -+ integrations: [lit(), vue()] |
134 | | - }); |
135 | | -``` |
136 | | - |
137 | | -The correct order might be different depending on the underlying cause of the problem. This is not guaranteed to fix every issue however, and some libraries cannot be used if you are using the Lit integration because of this. |
138 | | - |
139 | | -### Strict package managers |
140 | | - |
141 | | -When using a [strict package manager](https://pnpm.io/pnpm-vs-npm#npms-flat-tree) like `pnpm`, you may get an error such as `ReferenceError: module is not defined` when running your site. To fix this, hoist Lit dependencies with an `.npmrc` file: |
| 17 | +## Contributing |
142 | 18 |
|
143 | | -```ini |
144 | | -# .npmrc |
145 | | -public-hoist-pattern[]=*lit* |
146 | | -``` |
| 19 | +This package is maintained by Astro's Core team. You're welcome to submit an issue or PR! These links will help you get started: |
147 | 20 |
|
148 | | -### Limitations |
| 21 | +- [Contributor Manual][contributing] |
| 22 | +- [Code of Conduct][coc] |
| 23 | +- [Community Guide][community] |
149 | 24 |
|
150 | | -The Lit integration is powered by `@lit-labs/ssr` which has some limitations. See their [limitations documentation](https://www.npmjs.com/package/@lit-labs/ssr#user-content-notes-and-limitations) to learn more. |
| 25 | +## License |
151 | 26 |
|
152 | | -## Contributing |
| 27 | +MIT |
153 | 28 |
|
154 | | -This package is maintained by Astro's Core team. You're welcome to submit an issue or PR! |
| 29 | +Copyright (c) 2023–present [Astro][astro] |
155 | 30 |
|
156 | | -[astro-integration]: https://docs.astro.build/en/guides/integrations-guide/ |
157 | | -[astro-ui-frameworks]: https://docs.astro.build/en/core-concepts/framework-components/#using-framework-components |
| 31 | +[astro]: https://astro.build/ |
| 32 | +[docs]: https://docs.astro.build/en/guides/integrations-guide/lit/ |
| 33 | +[contributing]: https://github.com/withastro/astro/blob/main/CONTRIBUTING.md |
| 34 | +[coc]: https://github.com/withastro/.github/blob/main/CODE_OF_CONDUCT.md |
| 35 | +[community]: https://github.com/withastro/.github/blob/main/COMMUNITY_GUIDE.md |
| 36 | +[discord]: https://astro.build/chat/ |
| 37 | +[issues]: https://github.com/withastro/astro/issues |
| 38 | +[astro-integration]: https://docs.astro.build/en/guides/integrations-guide/ |
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