rehype-stringify
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!Chatchat-badgechatrehype plugin to add support for serializing to HTML.
Contents
* [`unified().use(rehypeStringify[, options])`](#unifieduserehypestringify-options)
* [`CharacterReferences`](#characterreferences)
* [`Options`](#options)
What is this?
This package is a unified (rehype) plugin that defines how to take a syntax tree as input and turn it into serialized HTML. When it’s used, HTML is serialized as the final result.See the monorepo readmerehype for info on what the rehype ecosystem is.
When should I use this?
This plugin adds support to unified for serializing HTML. If you also need to parse HTML, you can alternatively userehype
rehype-core, which combines unified,
rehype-parse
rehype-parse, and this plugin.When you are in a browser, trust your content, don’t need formatting options, and value a smaller bundle size, you can use
rehype-dom-stringify
rehype-dom-stringify instead.If you don’t use plugins and have access to a syntax tree, you can directly use
hast-util-to-html
hast-util-to-html, which is used inside this plugin.
rehype focusses on making it easier to transform content by abstracting such
internals away.A different plugin,
rehype-format
rehype-format, improves the readability
of HTML source code as it adds insignificant but pretty whitespace between
elements.
There is also the preset rehype-minify
rehype-minify for when you want the
inverse: minified and mangled HTML.Install
This package is ESM onlyesm. In Node.js (version 16+), install with npm:npm install rehype-stringify
In Deno with
esm.sh
esmsh:import rehypeStringify from 'https://esm.sh/rehype-stringify@10'
In browsers with
esm.sh
esmsh:<script type="module">
import rehypeStringify from 'https://esm.sh/rehype-stringify@10?bundle'
</script>
Use
Say we have the following moduleexample.js
:import remarkRehype from 'remark-rehype'
import rehypeStringify from 'rehype-stringify'
import remarkGfm from 'remark-gfm'
import remarkParse from 'remark-parse'
import {unified} from 'unified'
const file = await unified()
.use(remarkParse)
.use(remarkGfm)
.use(remarkRehype)
.use(rehypeStringify)
.process('# Hi\n\n*Hello*, world!')
console.log(String(file))
…running that with
node example.js
yields:<h1>Hi</h1>
<p><em>Hello</em>, world!</p>
API
This package exports no identifiers. The default export isrehypeStringify
api-rehype-stringify.unified().use(rehypeStringify[, options])
Plugin to add support for serializing to HTML.Parameters
options
(Options
api-options, optional)
— configuration
Returns
Nothing (undefined
).CharacterReferences
How to serialize character references (TypeScript type).⚠️ Note: omitOptionalSemicolons
creates what HTML calls “parse errors”
but is otherwise still valid HTML — don’t use this except when building a
minifier.
Omitting semicolons is possible for certain named and numeric references in
some cases.
⚠️ Note:useNamedReferences
can be omitted when usinguseShortestReferences
.
Fields
useNamedReferences
(boolean
, default:false
)
— prefer named character references (`&`) where possible
omitOptionalSemicolons
(boolean
, default:false
)
— whether to omit semicolons when possible
useShortestReferences
(boolean
, default:false
)
— prefer the shortest possible reference, if that results in less bytes
Options
Configuration (TypeScript type).⚠️ Danger: only setallowDangerousCharacters
andallowDangerousHtml
if you completely trust the content.
👉 Note:allowParseErrors
,bogusComments
,tightAttributes
, andtightDoctype
intentionally create parse errors in markup (how parse errors are handled is well defined, so this works but isn’t pretty).
👉 Note: this is not an XML serializer.
It supports SVG as embedded in HTML.
It does not support the features available in XML.
Use xast-util-to-xml
xast-util-to-xml to serialize XML.
Fields
allowDangerousCharacters
(boolean
, default:false
)
— do not encode some characters which cause XSS vulnerabilities in older
browsers
allowDangerousHtml
(boolean
, default:false
)
— allow [`Raw`][raw] nodes and insert them as raw HTML; when `false`, `Raw`
nodes are encoded
allowParseErrors
(boolean
, default:false
)
— do not encode characters which cause parse errors (even though they
work), to save bytes; not used in the SVG space.
bogusComments
(boolean
, default:false
)
— use “bogus comments” instead of comments to save byes: `<?charlie>`
instead of `<!--charlie-->`
characterReferences
(CharacterReferences
api-character-references,
optional)
— configure how to serialize character references
closeEmptyElements
(boolean
, default:false
)
— close SVG elements without any content with slash (`/`) on the opening
tag instead of an end tag: `<circle />` instead of `<circle></circle>`;
see `tightSelfClosing` to control whether a space is used before the slash;
not used in the HTML space
closeSelfClosing
(boolean
, default:false
)
— close self-closing nodes with an extra slash (`/`): `<img />` instead of
`<img>`; see `tightSelfClosing` to control whether a space is used before
the slash; not used in the SVG space.
collapseEmptyAttributes
(boolean
, default:false
)
— collapse empty attributes: get `class` instead of `class=""`; not used in
the SVG space; boolean attributes (such as `hidden`) are always collapsed
omitOptionalTags
(boolean
, default:false
)
— omit optional opening and closing tags; to illustrate, in
`<ol><li>one</li><li>two</li></ol>`, both `</li>` closing tags can be
omitted, the first because it’s followed by another `li`, the last because
it’s followed by nothing; not used in the SVG space
preferUnquoted
(boolean
, default:false
)
— leave attributes unquoted if that results in less bytes; not used in the
SVG space
quote
('"'
or"'"
, default:'"'
)
— preferred quote to use
quoteSmart
(boolean
, default:false
)
— use the other quote if that results in less bytes
space
('html'
or'svg'
, default:'html'
)
— which space the document is in; when an `<svg>` element is found in the
HTML space, this package already automatically switches to and from the SVG
tightAttributes
(boolean
, default:false
)
— join attributes together, without whitespace, if possible: get
`class="a b"title="c d"` instead of `class="a b" title="c d"` to save
bytes; not used in the SVG space
tightCommaSeparatedLists
(boolean
, default:false
)
— join known comma-separated attribute values with just a comma (`,`),
instead of padding them on the right as well (`,␠`, where `␠` represents a
space)
tightDoctype
(boolean
, default:false
)
— drop unneeded spaces in doctypes: `<!doctypehtml>` instead of
`<!doctype html>` to save bytes
tightSelfClosing
(boolean
, default:false
).
— do not use an extra space when closing self-closing elements: `<img/>`
instead of `<img />`; only used if `closeSelfClosing: true` or
`closeEmptyElements: true`
upperDoctype
(boolean
, default:false
).
— use a `<!DOCTYPE…` instead of `<!doctype…`; useless except for XHTML
voids
(Array<string>
, default:
[`html-void-elements`][html-void-elements])
— tag names of elements to serialize without closing tag; not used in the
SVG space
Syntax
HTML is serialized according to WHATWG HTML (the living standard), which is also followed by all browsers.Syntax tree
The syntax tree format used in rehype is hast.Types
This package is fully typed with TypeScript. It exports the additional typesCharacterReferences
api-character-references and
Options
api-options.Compatibility
Projects maintained by the unified collective are compatible with maintained versions of Node.js.When we cut a new major release, we drop support for unmaintained versions of Node. This means we try to keep the current release line,
rehype-stringify@^10
,
compatible with Node.js 16.Security
As rehype works on HTML, and improper use of HTML can open you up to a cross-site scripting (XSS)xss attack, use of rehype can also be unsafe. Userehype-sanitize
rehype-sanitize to make the tree safe.Use of rehype plugins could also open you up to other attacks. Carefully assess each plugin and the risks involved in using them.
For info on how to submit a report, see our security policysecurity.
Contribute
Seecontributing.md
contributing in rehypejs/.github
health for ways
to get started.
See support.md
support for ways to get help.This project has a code of conductcoc. By interacting with this repository, organization, or community you agree to abide by its terms.
Sponsor
Support this effort and give back by sponsoring on OpenCollectivecollective!
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