unified

Project:rehypejs/rehype

Package:rehype-parse@6.0.2

  1. Dependencies:3Β·Dependents:79
  2. HTML parser for rehype
  1. html 100
  2. tree 40
  3. syntax 30
  4. ast 27
  5. parse 17
  6. abstract 10

rehype-parse

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rehype plugin to parse HTML. Parser for unified. Parses HTML to hast syntax trees. Used in the rehype processor but can be used on its own as well.

If you’re in a browser, trust the content, and value a smaller bundle size, use rehype-dom-parse.

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πŸ₯‡ Netlify


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Install

npm:

npm install rehype-parse

Use

This example shows how we can parse HTML with this module and configure it to emit parse errors except for duplicate attributes. Then we transform HTML to Markdown with rehype-remark and finally compile that Markdown with remark-stringify.

Say we have the following file, example.html, with a few errors:

<!doctypehtml>
<title class="a" class="b">Hello…</title>
<h1/>World!</h1>

…and our script, example.js, looks as follows:

var vfile = require('to-vfile')
var report = require('vfile-reporter')
var unified = require('unified')
var parse = require('rehype-parse')
var rehype2remark = require('rehype-remark')
var stringify = require('remark-stringify')

unified()
  .use(parse, {emitParseErrors: true, duplicateAttribute: false})
  .use(rehype2remark)
  .use(stringify)
  .process(vfile.readSync('example.html'), function(err, file) {
    console.error(report(err || file))
    console.log(String(file))
  })

Now, running node example yields:

example.html
  1:10-1:10  warning  Missing whitespace before doctype name                      missing-whitespace-before-doctype-name                 parse-error
    3:1-3:6  warning  Unexpected trailing slash on start tag of non-void element  non-void-html-element-start-tag-with-trailing-solidus  parse-error

⚠ 2 warnings
# World!

API

processor.use(parse[, options])

Configure processor to parse HTML and create a hast syntax tree.

options
options.fragment

Specify whether to parse a fragment (boolean, default: false), instead of a complete document. In document mode, unopened html, head, and body elements are opened in just the right places.

options.space

⚠️ rehype is not an XML parser. It support SVG as embedded in HTML, but not the features available in the rest of XML/SVG. Passing SVG files could strip useful information, but fragments of modern SVG should be fine.

Which space the document is in ('svg' or 'html', default: 'html').

If an svg element is found in the HTML space, stringify automatically switches to the SVG space when entering the element, and switches back when exiting.

Note: make sure to set fragment: true if space: 'svg'.

options.emitParseErrors

⚠️ Parse errors are currently being added to HTML. Not all errors emitted by parse5 (or rehype-parse) are specced yet. Some documentation may still be missing.

Emit parse errors while parsing on the vfile (boolean, default: false).

Setting this to true starts emitting HTML parse errors.

Specific rules can be turned off by setting them to false (or 0). The default, when emitParseErrors: true, is true (or 1), and means that rules emit as warnings. Rules can also be configured with 2, to turn them into fatal errors.

The specific parse errors that are currently supported are detailed below:

options.verbose

Patch extra positional information (boolean, default: false). If specified, the following element:

<img src="#" alt>

…has the following data:

{ position:
   { opening:
      { start: { line: 1, column: 1, offset: 0 },
        end: { line: 1, column: 18, offset: 17 } },
     closing: null,
     properties:
      { src:
         { start: { line: 1, column: 6, offset: 5 },
           end: { line: 1, column: 13, offset: 12 } },
        alt:
         { start: { line: 1, column: 14, offset: 13 },
           end: { line: 1, column: 17, offset: 16 } } } } }

parse.Parser

Access to the parser, if you need it.

Security

As rehype works on HTML, and improper use of HTML can open you up to a cross-site scripting (XSS) attack, use of rehype can also be unsafe. Use rehype-sanitize to make the tree safe.

Contribute

See contributing.md in rehypejs/.github for ways to get started. See support.md for ways to get help. Ideas for new plugins and tools can be posted in rehypejs/ideas.

A curated list of awesome rehype resources can be found in awesome rehype.

This project has a Code of Conduct. By interacting with this repository, organisation, or community you agree to abide by its terms.

License

MIT Β© Titus Wormer