syzoj-renderer

SYZOJ's renderer for markdown, math and highlight.

Example

let { markdown, highlight } = require('syzoj-renderer');

console.log(await markdown(text));
console.log(await highlight(code, language));

API

async markdown(text, [cache, filterFunction, options])

text is the Markdown text to be rendered.

cache is null or a object with two functions to manipulate a Key-Value store (key is hashed before passing to cache):

• async get(string key)
• async set(string key, string value)

filterFunction(html) is a function to filter rendered HTML. It can be used to prevent XSS attack. Should return filtered HTML.

options is a object, may contain:

• markdownIt: Overrides default options in new MarkdownIt(options). (See markdown-it)
• markdownItMath: Overrides default options in markdownIt.use(MathdownItMath, options). (See markdown-it-math-loose)
• markdownItMergeCells: Set to false to disable markdown-it-merge-cells in markdown tables, which will merge adjacent cells with same content in tables
• highlight: Same as highlight's options parameter, used when highlighting code in markdown.

Return rendered HTML. Won't throw.

async highlight(code, language[, cache, options])

Highlight some code with pygments.

code is the code to be highlighted. language is code's language.

cache is same as the parameter in markdown().

options is a object, may contain:

• pygments: Overrides default options in Pygments.pygmentize(code, options). (See pygments-promise)
• highlighter: Pass a function async function (code, language) to replace the defualt pygments highlighter. If a function is passed, pygments won't be used and pygments option will be ignored.
• wrapper: An array [before, after]. Highlighted code's HTML will be wrapped by before and after. Defaults to ['<pre><code>', '</code></pre>'].

Return highlighted code in HTML. Won't throw.

Notes

• Markdown backend is markdown-it.
  • GFM is supported.
  • By default, linkify and html are enabled, typographer and breaks are disabled.
• By default, code highlight's backend is pygments, which requires pygments to be installed.
  • If no pygmentize is available, it'll always return unhighlighted code.
  • pygmentize's default commandline arguments are: pygmentize -l <language> -f html -P nowrap=false -P classprefix=pl-.
  • A theme CSS is required to display highlighted code properly. See Generating styles section of pygments's document.
• Math backend is mathjax-node-page.
  • Maths are rendered to <svg> HTML elements, dist/math.css is required to display properly.
  • Maths with spaces within dollar sign like $ a+b $ will work.
  • Complex maths like $ \sum\limits_{i=0}^na_i $ won't be broken by Markdown.
  • To ensure each document's math rendering state isolated, \require is disabled.
  • Maths that failed to render would result in displaying error message.

License

AGPL-3.0. Contact me if you really want this to be MIT license.