hexo-renderer-markdown-it

This renderer plugin uses Markdown-it as a render engine on Hexo. Adds support for Markdown and CommonMark.

Main Features

• Support for Markdown, GFM and CommonMark
• Extensive configuration
• Faster than the default renderer | hexo-renderer-marked
• Safe ID for headings
• Anchors for headings with ID
• Footnotes
• <sub> H₂O
• <sup> x²
• <ins> Inserted

Installation

Warning: make sure you're inside the main hexo directory before starting this guide.

A default Hexo installation will include a markdown renderer plugin which uses marked, so you will have to remove it if you want to use hexo-renderer-markdown-it.

$ npm un hexo-renderer-marked --save

If you have already removed the default renderer, and others you might of added, you can now safely install hexo-renderer-markdown-it

$ npm i hexo-renderer-markdown-it --save

Options

markdown:
  preset: 'default'
  render:
    html: true
    xhtmlOut: false
    langPrefix: 'language-'
    breaks: true
    linkify: true
    typographer: true
    quotes: '“”‘’'
  enable_rules:
  disable_rules:
  plugins:
  anchors:
    level: 2
    collisionSuffix: ''
    permalink: false
    permalinkClass: 'header-anchor'
    permalinkSide: 'left'
    permalinkSymbol: '¶'
    case: 0
    separator: '-'
  images:
    lazyload: false
    prepend_root: false
    post_asset: false
  inline: false  # https://markdown-it.github.io/markdown-it/#MarkdownIt.renderInline

See below for more details.

Advanced Configuration

Preset options

markdown:
  preset: 'default'

• "commonmark" - configures parser to strict CommonMark mode.
• "default" - similar to GFM, used when no preset name given. Enables all available rules, but still without html, typographer & autolinker.
• "zero" - all rules disabled. Useful to quickly setup your config via .enable(). For example, when you need only bold and italic markup and nothing else.

Note that the default render and anchor options override some options in the preset. If you prefer to have the preset only:

markdown:
  preset: 'default'
  render:
  anchors:

Render options

html

The html setting defines whether or not HTML content inside the document should be escaped or passed to the final result.

html: true # Doesn't escape HTML content
    ## OR
html: false # Escapes HTML content so the tags will appear as text.

xhtmlOut

The xhtmlOut setting defines whether the parser will export fully XHTML compatible tags. This only needs to be true for complete CommonMark support.

xhtmlOut: true # Parser produces fully XHTML compliant code.
               # Ex: A line breaks will be <br />
    ## OR
xhtmlOut: false # Parser will not produce XHTML compliant code.
                # Ex: A line break will be <br>

breaks

Makes line breaks in the source file will be parsed into <br> tags. So every time you press the Enter key you will create a line break, which is not the default Markdown, CommonMark, or GFM behaviour.

breaks: true # Parser produces `<br>` tags every time there is a line break in the source document.
    ## OR
breaks: false # Parser will ignore line breaks in the source document.
              #Default double line break creates paragraph is still supported

langPrefix

Add a prefix to the class name of code blocks (when a language is specified).

langPrefix: 'language-' # default

This option only applies when both Hexo's built-in highlighters are disabled.

Example:

langPrefix: 'lang-'

Source:

``` js
example
```

HTML:

<pre>
<code class="lang-js">example</code>
</pre>

linkify

The parser has the ability to inline links pasted directly into the text. If you write a piece of text that looks like a link it will be rendered as <a src="http://example.com">http://example.com</a>.

linkify: true # Returns text links as proper links inlined with the paragraph.
    ## OR
linkify: false # Returns text links as text.

typographer

This is enables the substitution for common typography elements like ©, curly quotes, dashes, etc.

typographer: true # Substitution of common typographical elements will take place.
    ## OR
typographer: false # No substitution, so dumb quotes will remain dumb quotes, etc.

quotes

Defines the double and single quotes used for substituting dumb quotes if typographer is set to true.

quotes: '“”‘’' # "double" will be turned into “single”
               # 'single' will be turned into ‘single’
    ## OR
quotes: '«»“”' # "double" will be turned into «single»
               # 'single' will be turned into “single”

Example configuration

markdown:
  render:
    html: true
    xhtmlOut: false
    breaks: false
    linkify: true
    typographer: true
    quotes: '“”‘’'

Manage rules

Certain rules are enabled or disabled depending on the preset. For example, "zero" preset disables all rules, to enable specific rules:

markdown:
  preset: 'zero'

  # Single rule
  enable_rules: 'link'

  # Multiple rules
  enable_rules:
    - 'link'
    - 'image'

"default" preset enables all rules, to disable specific rules:

markdown:
  preset: 'default'

  # Single rule
  disable_rules: 'link'

  # Multiple rules
  disable_rules:
    - 'link'
    - 'image'

Available rules

Since the rules are subject to change, it's better to check the Markdown-it's source code for up-to-date rules. Look for the _rules variable in the following files:

• parser_block.js
• parser_core.js
• parser_inline.js

Automatic Headline ID's

Enables you to automatically create ID's for the headings so you can link back to them. A valid html document cannot have two elements with duplicate id value, for example if title id is already used, subsequent title values will be updated to title-2, title-3 and so on.

Default options:

markdown:
  anchors:
    # Minimum level for ID creation. (Ex. h2 to h6)
    level: 2
    # A suffix that is prepended to the number given if the ID is repeated.
    collisionSuffix: ''
    # If `true`, creates an anchor tag with a permalink besides the heading.
    permalink: false
    # Class used for the permalink anchor tag.
    permalinkClass: header-anchor
    # Set to 'right' to add permalink after heading
    permalinkSide: 'left'
    # The symbol used to make the permalink
    permalinkSymbol: ¶
    # Transform anchor to (1) lower case; (2) upper case
    case: 0
    # Replace space with a character
    separator: '-'

Plugins

Included plugins:

• markdown-it-abbr
• markdown-it-attrs
• markdown-it-cjk-breaks
• markdown-it-container
• markdown-it-deflist
• markdown-it-emoji
• markdown-it-footnote
• markdown-it-ins
• markdown-it-mark
• markdown-it-sub
• markdown-it-sup

Plugins are not enabled by default, to enable:

markdown:
  plugins:
    - markdown-it-abbr
    # installed external plugins also can be enabled
    - markdown-it-table-of-contents

Plugin option

markdown:
  plugins:
    - name: 'markdown-it-emoji'
      options:
        shortcuts:
          laughing: ':D'
    - name: 'other-plugin'
      options: ...

Extensibility

This plugin overrides some default behaviors of how markdown-it plugin renders the markdown into html, to integrate with the Hexo ecosystem. It is possible to override this plugin too, without resorting to forking the whole thing.

For example, to enable unsafe links (which is disabled by default):

hexo.extend.filter.register('markdown-it:renderer', function(md) {
  const { config } = this; // Optional, parse user config from _config.yml
  md.validateLink = function() { return true; };
});

// Specify custom function in plugin option
const { slugize } = require('hexo-util');
const opts = hexo.config.markdown.anchors;
const mdSlugize = (str) => {
  return slugize(str, { transform: opts.case, ...opts });
};

hexo.extend.filter.register('markdown-it:renderer', function(md) {
  md.use(require('markdown-it-table-of-contents'), {
    includeLevel: [2,3,4],
    slugify: mdSlugize
  });
});

Save the file in "scripts/" folder and run Hexo as usual.

Refer to markdown-it API documentation.

Frequently Asked Questions

Missing Styles of GFM Task Lists

In general, adding the following styles to the theme can solve the problem.

li.task-list-item {
  list-style-type: none;
}

li.task-list-item .task-list-item-checkbox {
  margin: 0 0.2em 0.25em -1.6em;
}

How can I add math support?

First, install KaTeX plugin for markdown-it.

npm install katex @renbaoshuo/markdown-it-katex

Then add @renbaoshuo/markdown-it-katex to plugins list.

plugins:
  - '@renbaoshuo/markdown-it-katex'
  # Other plugins...

If you need to allow spaces before and after delimiters (e.g. $ 1 + 1 = 2 $), set the skipDelimitersCheck option to true:

plugins:
  - name: '@renbaoshuo/markdown-it-katex'
    options:
      skipDelimitersCheck: true

Don't forget to include the KaTeX stylesheet in your html:

<link
  rel="stylesheet"
  href="https://cdn.jsdelivr.net/npm/katex/dist/katex.min.css"
/>

How can I merge table cells with the same content?

Install the markdown-it-merge-cells plugin.

npm install markdown-it-merge-cells

Then add the plugin to plugins list.

plugins:
  - markdown-it-merge-cells
  # Other plugins...

Requests and bug reports

If you have any feature requests or bugs to report, you're welcome to file an issue.