hast-util-classnames

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[hast][] utility to set classes.

Contents

* What is this?
* When should I use this?
* Install
* Use
* API
* [classnames([node, ]…conditionals)](#classnamesnode-conditionals)
* ConditionalPrimitive
* ConditionalMap
* Conditional
* Types
* Compatibility
* Security
* Related
* Contribute
* License

What is this?

This package is a utility that takes lets you more easily set class names on
elements.

When should I use this?

You can use this package when you find that that you’re repeating yourself
a lot when working with classes in the syntax tree.

Install

This package is [ESM only][esm].
In Node.js (version 16+), install with [npm][]:

``sh
npm install hast-util-classnames
`

In Deno with [esm.sh][esmsh]:

`js
import {classnames} from 'https://esm.sh/hast-util-classnames@3'
`

In browsers with [esm.sh][esmsh]:

`html

`

Use

`js
import {h} from 'hastscript'
import {classnames} from 'hast-util-classnames'

console.log(classnames('alpha bravo', {bravo: false}, [123, 'charlie']))

const node = h('p.alpha', 'Hi!')
console.log(classnames(node, 'bravo', ['charlie', {delta: false, echo: 1}]))
`

Yields:

`js
['alpha', '123', 'charlie']
{
type: 'element',
tagName: 'p',
properties: {className: ['alpha', 'bravo', 'charlie', 'echo']},
children: [{type: 'text', value: 'Hi!'}]
}
`

API

This package exports the identifier [classnames][api-classnames].
There is no default export.

$3

Merge classes.

This function has two signatures, depending on whether a node was passed.

###### Signatures

* (node: Node, ...conditionals: Array) => Node
* (...conditionals: Array) => Array

###### Parameters

* node ([Node][node])
— optionally, node whose classes to append to (must be
[Element][element])
* conditionals ([Array][api-conditional])
— class configuration to merge

###### Returns

The given node ([Node][node]), if any, or a list of strings (Array).

$3

Basic class names (TypeScript type).

###### Type

`ts
type ConditionalPrimitive = number | string
`

$3

Map of class names as keys, with whether they’re turned on or not as values.

###### Type

`ts
type ConditionalMap = Record
`

$3

Different ways to turn class names on or off (TypeScript type).

###### Type

`ts
type Conditional =
| Array<
| Array
| ConditionalMap
| ConditionalPrimitive
>
| ConditionalMap
| ConditionalPrimitive
| null
| undefined
`

Types

This package is fully typed with [TypeScript][].
It exports the additional types [Conditional][api-conditional],
[ConditionalMap][api-conditional-map], and
[ConditionalPrimitive][api-conditional-primitive].

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, hast-util-classnames@^3,
compatible with Node.js 16.

Security

Classes are typically not harmful, however, if someone were able to inject
classes, it could mean that user-provided content looks like official content,
which may cause security problems due to impersonation.
Either do not use user input in classnames or use
[hast-util-sanitize][hast-util-sanitize] to clean the tree.

Related

* hastscript
— create hast trees
* hast-util-from-selector
— parse CSS selectors to hast nodes
* hast-util-has-property
— check if a node has a property
* hast-util-is-element
— check if a node is a (certain) element

Contribute

See [contributing.md][contributing] in [syntax-tree/.github][health] for
ways to get started.
See [support.md`][support] for ways to get help.

This project has a [code of conduct][coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.

License

[MIT][license] © [Titus Wormer][author]

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[collective]: https://opencollective.com/unified

[chat-badge]: https://img.shields.io/badge/chat-discussions-success.svg

[chat]: https://github.com/syntax-tree/unist/discussions

[npm]: https://docs.npmjs.com/cli/install

[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c

[esmsh]: https://esm.sh

[typescript]: https://www.typescriptlang.org

[license]: license

[author]: https://wooorm.com

[health]: https://github.com/syntax-tree/.github

[contributing]: https://github.com/syntax-tree/.github/blob/main/contributing.md

[support]: https://github.com/syntax-tree/.github/blob/main/support.md

[coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md

[hast]: https://github.com/syntax-tree/hast

[node]: https://github.com/syntax-tree/hast#nodes

[element]: https://github.com/syntax-tree/hast#element

[hast-util-sanitize]: https://github.com/syntax-tree/hast-util-sanitize

[api-classnames]: #classnamesnode-conditionals

[api-conditional]: #conditional

[api-conditional-map]: #conditionalmap

[api-conditional-primitive]: #conditionalprimitive