1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
---
layout: ~/layouts/Main.astro
title: Markdown
---
Astro comes with out-of-the-box Markdown support powered by the expansive [remark](https://remark.js.org/) ecosystem.
## Remark and Rehype Plugins
In addition to [custom components inside the `<Markdown>` component](#markdown-component), Astro comes with [GitHub-flavored Markdown](https://github.github.com/gfm/) support, [Footnotes](https://github.com/remarkjs/remark-footnotes) syntax, [Smartypants](https://github.com/silvenon/remark-smartypants), and syntax highlighting via [Prism](https://prismjs.com/) pre-enabled.
Also, Astro supports third-party plugins for Markdown. You can provide your plugins in `astro.config.mjs`.
> **Note** Enabling custom `remarkPlugins` or `rehypePlugins` removes Astro's built-in support for [GitHub-flavored Markdown](https://github.github.com/gfm/) support, [Footnotes](https://github.com/remarkjs/remark-footnotes) syntax, [Smartypants](https://github.com/silvenon/remark-smartypants). You must explicitly add these plugins to your `astro.config.mjs` file, if desired.
## Add a markdown plugin in Astro
If you want to add a plugin, you need to install the npm package dependency in your project and then update the `markdownOptions.remarkPlugins` or `markdownOptions.rehypePlugins` depends on what plugin you want to have:
```js
// astro.config.js
export default {
markdownOptions: {
remarkPlugins: [
// Add a Remark plugin that you want to enable for your project.
// If you need to provide options for the plugin, you can use an array and put the options as the second item.
// 'remark-slug',
// ['remark-autolink-headings', { behavior: 'prepend'}],
]
rehypePlugins: [
// Add a Rehype plugin that you want to enable for your project.
// If you need to provide options for the plugin, you can use an array and put the options as the second item.
// 'rehype-slug',
// ['rehype-autolink-headings', { behavior: 'prepend'}],
]
},
};
```
You can provide names of the plugins as well as import them:
```js
// astro.config.js
export default {
markdownOptions: {
remarkPlugins: [import('remark-slug'), [import('remark-autolink-headings'), { behavior: 'prepend' }]],
},
};
```
### Markdown Pages
Astro treats any `.md` files inside of the `/src/pages` directory as pages. These pages are processed as plain markdown files and do not support components. If you're looking to embed rich components in your markdown, take a look at the [Markdown Component](#astros-markdown-component) section.
`layout`
The only special Frontmatter key is `layout`, which defines the relative path to an `.astro` component which should wrap your Markdown content.
`src/pages/index.md`
```jsx
---
layout: ../layouts/main.astro
---
# Hello World!
```
Layout files are normal `.astro` components. Any Frontmatter defined in your `.md` page will be exposed to the Layout component as the `content` prop. `content` also has an `astro` key which holds special metadata about your file, like the complete Markdown `source` and a `headings` object.
Keep in mind that the only guaranteed variables coming from the `content` prop object are `astro` and `url`. An example of what a blog post `content` object might look like is as follows:
```json
{
/** Frontmatter from blog post
"title": "",
"date": "",
"author": "",
"description": "",
**/
"astro": {
"headers": [],
"source": ""
},
"url": ""
}
```
The rendered Markdown content is placed into the default `<slot />` element.
`src/layouts/main.astro`
```jsx
---
const { content } = Astro.props;
---
<html>
<head>
<title>{content.title}</title>
</head>
<body>
<slot/>
</body>
</html>
```
### Astro's Markdown Component
Astro has a dedicated component used to let you render your markdown as HTML components. This is a special component that is only exposed to `.astro` files. To use the `<Markdown>` component, within yout frontmatter block use the following import statement:
```jsx
---
import { Markdown } from 'astro/components';
---
```
You can utilize this within your `.astro` file by doing the following:
```jsx
---
import { Markdown } from 'astro/components';
---
<Layout>
<Markdown>
# Hello world!
The contents inside here is all in markdown.
</Markdown>
</Layout>
```
`<Markdown>` components provide more flexibility and allow you to use plain HTML or custom components. For example:
````jsx
---
// For now, this import _must_ be named "Markdown" and _must not_ be wrapped with a custom component
// We're working on easing these restrictions!
import { Markdown } from 'astro/components';
import Layout from '../layouts/main.astro';
import MyFancyCodePreview from '../components/MyFancyCodePreview.tsx';
const expressions = 'Lorem ipsum';
---
<Layout>
<Markdown>
# Hello world!
**Everything** supported in a `.md` file is also supported here!
There is _zero_ runtime overhead.
In addition, Astro supports:
- Astro {expressions}
- Automatic indentation normalization
- Automatic escaping of expressions inside code blocks
```jsx
// This content is not transformed!
const object = { someOtherValue };
```
- Rich component support like any `.astro` file!
- Recursive Markdown support (Component children are also processed as Markdown)
<MyFancyCodePreview:visible>
```jsx
const object = { someOtherValue };
```
</MyFancyCodePreview:visible>
</Markdown>
</Layout>
````
### Remote Markdown
If you have Markdown in a remote source, you may pass it directly to the Markdown component through the `content` attribute. For example, the example below fetches the README from Snowpack's Github repository and renders it as HTML.
```jsx
---
import { Markdown } from 'astro/components';
const content = await fetch('https://raw.githubusercontent.com/snowpackjs/snowpack/main/README.md').then(res => res.text());
---
<Layout>
<Markdown content={content} />
</Layout>
```
There might be times when you want to combine both dynamic, and static markdown. If that is the case, you can nest `<Markdown>` components with each other to get the best of both worlds.
```jsx
---
import { Markdown } from 'astro/components';
const content = await fetch('https://raw.githubusercontent.com/snowpackjs/snowpack/main/README.md').then(res => res.text());
---
<Layout>
<Markdown>
## Markdown example
Here we have some __Markdown__ code. We can also dynamically render content from remote places.
<Markdown content={content} />
</Mardown>
</Layout>
```
### Security FAQs
**Aren't there security concerns to rendering remote markdown directly to HTML?**
Yes! Just like with regular HTML, improper use of the `Markdown` component can open you up to a [cross-site scripting (XSS)](https://en.wikipedia.org/wiki/Cross-site_scripting) attack. If you are rendering untrusted content, be sure to _sanitize your content **before** rendering it_.
**Why not use a prop like React's `dangerouslySetInnerHTML={{ __html: content }}`?**
Rendering a string of HTML (or Markdown) is an extremely common use case when rendering a static site and you probably don't need the extra hoops to jump through. Rendering untrusted content is always dangerous! Be sure to _sanitize your content **before** rendering it_.
|
