rehype-parse
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
.
Support this effort and give back by sponsoring on OpenCollective!
Install
This package is ESM only:
Node 12+ is needed to use it and it must be import
ed instead of require
d.
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 serialize 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:
import {readSync} from 'to-vfile'
import {reporter} from 'vfile-reporter'
import {unified} from 'unified'
import rehypeParse from 'rehype-parse'
import rehypeRemark from 'rehype-remark'
import remarkStringify from 'remark-stringify'
const file = readSync('example.html')
unified()
.use(rehypeParse, {emitParseErrors: true, duplicateAttribute: false})
.use(rehypeRemark)
.use(remarkStringify)
.process(file)
.then((file) => {
console.error(reporter(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
This package exports no identifiers.
The default export is rehypeParse
.
unified().use(rehypeParse[, 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, parse
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, organization, or community you agree to
abide by its terms.
License
MIT © Titus Wormer