rehype-external-links
rehype plugin to add rel
(and target
) to external links.
Contents
- What is this?
- When should I use this?
- Install
- Use
- API
- Types
- Compatibility
- Security
- Contribute
- License
What is this?
This package is a unified (rehype) plugin to add rel
(and target
)
attributes to external links.
It is particularly useful when displaying user content on your reputable site,
because users could link to disreputable sources (spam, scams, etc), as search
engines and other bots will discredit your site for linking to them (or
legitimize their sites).
In short: linking to something signals trust, but you can’t trust users.
This plugin adds certain rel
attributes to prevent that from happening.
unified is a project that transforms content with abstract syntax trees
(ASTs).
rehype adds support for HTML to unified.
hast is the HTML AST that rehype uses.
This is a rehype plugin that adds rel
(and target
) to <a>
s in the AST.
When should I use this?
This project is useful when you want to display user content from authors you don’t trust (such as comments), as they might include links you don’t endorse, on your website.
Install
This package is ESM only. In Node.js (version 16+), install with npm:
npm install rehype-external-links
In Deno with esm.sh
:
import rehypeExternalLinks from 'https://esm.sh/rehype-external-links@3'
In browsers with esm.sh
:
<script type="module">
import rehypeExternalLinks from 'https://esm.sh/rehype-external-links@3?bundle'
</script>
Use
Say our module example.js
contains:
import rehypeExternalLinks from 'rehype-external-links'
import remarkParse from 'remark-parse'
import remarkRehype from 'remark-rehype'
import rehypeStringify from 'rehype-stringify'
import {unified} from 'unified'
const file = await unified()
.use(remarkParse)
.use(remarkRehype)
.use(rehypeExternalLinks, {rel: ['nofollow']})
.use(rehypeStringify)
.process('[rehype](https://github.com/rehypejs/rehype)')
console.log(String(file))
…then running node example.js
yields:
<p><a href="https://github.com/rehypejs/rehype" rel="nofollow">rehype</a></p>
API
This package exports no identifiers.
The default export is rehypeExternalLinks
.
unified().use(rehypeExternalLinks[, options])
Automatically add rel
(and target
?) to external links.
Parameters
-
options
(Options
, optional) — configuration
Returns
Transform (Transformer
).
Notes
You should likely not configure target
.
You should at least set rel
to ['nofollow']
.
When using a target
, add noopener
and noreferrer
to avoid exploitation
of the window.opener
API.
When using a target
, you should set content
to adhere to accessibility
guidelines by giving users advanced warning when opening a new window.
CreateContent
Create a target for the element (TypeScript type).
Parameters
-
element
(Element
) — element to check
Returns
Content to add (Array<Node>
or Node
, optional).
CreateProperties
Create properties for an element (TypeScript type).
Parameters
-
element
(Element
) — element to check
Returns
Properties to add (Properties
, optional).
CreateRel
Create a rel
for the element (TypeScript type).
Parameters
-
element
(Element
) — element to check
Returns
rel
to use (Array<string>
, optional).
CreateTarget
Create a target
for the element (TypeScript type).
Parameters
-
element
(Element
) — element to check
Returns
target
to use (Target
, optional).
Options
Configuration (TypeScript type).
Fields
-
content
(Array<Node>
,CreateContent
, orNode
, optional) — content to insert at the end of external links; will be inserted in a<span>
element; useful for improving accessibility by giving users advanced warning when opening a new window -
contentProperties
(CreateProperties
orProperties
, optional) — properties to add to thespan
wrappingcontent
-
properties
(CreateProperties
orProperties
, optional) — properties to add to the link itself -
protocols
(Array<string>
, default:['http', 'https']
) — protocols to see as external, such asmailto
ortel
-
rel
(Array<string>
,CreateRel
, orstring
, default:['nofollow']
) — link types to hint about the referenced documents; pass an empty array ([]
) to not setrel
s on links; when using atarget
, addnoopener
andnoreferrer
to avoid exploitation of thewindow.opener
API -
target
(CreateTarget
orTarget
, optional) — how to display referenced documents; the default (nothing) is to not settarget
s on links -
test
(Test
, optional) — extra test to define which external link elements are modified; any test that can be given tohast-util-is-element
is supported
Target
Target (TypeScript type).
Type
type Target = '_blank' | '_parent' | '_self' | '_top'
Types
This package is fully typed with TypeScript.
It exports the additional types
CreateContent
,
CreateProperties
,
CreateRel
,
CreateTarget
,
Options
, and
Target
.
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-external-links@^3
,
compatible with Node.js 16.
This plugin works with rehype-parse
version 3+, rehype-stringify
version 3+,
rehype
version 4+, and unified
version 6+.
Security
Improper use of rehype-external-links
can open you up to a
cross-site scripting (XSS) attack.
Either do not combine this plugin with user content or use
rehype-sanitize
.
Contribute
See contributing.md
in rehypejs/.github
for ways
to get started.
See support.md
for ways to get help.
This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.