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
.
Read more about the unified collective on Medium »
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 © Titus Wormer