https://github.com/syntax-tree/hast-util-select
utility to add `querySelector`, `querySelectorAll`, and `matches` support for hast
https://github.com/syntax-tree/hast-util-select
hast hast-util html matches queryselector select selectall util
Last synced: 3 months ago
JSON representation
utility to add `querySelector`, `querySelectorAll`, and `matches` support for hast
- Host: GitHub
- URL: https://github.com/syntax-tree/hast-util-select
- Owner: syntax-tree
- License: mit
- Created: 2017-04-09T19:07:55.000Z (over 8 years ago)
- Default Branch: main
- Last Pushed: 2025-02-19T14:34:38.000Z (8 months ago)
- Last Synced: 2025-03-20T21:11:33.056Z (7 months ago)
- Topics: hast, hast-util, html, matches, queryselector, select, selectall, util
- Language: JavaScript
- Homepage: https://unifiedjs.com
- Size: 263 KB
- Stars: 41
- Watchers: 8
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: license
Awesome Lists containing this project
- awesome-syntax-tree - hast-util-select - `querySelector`, `querySelectorAll`, and `matches`. (hast utilities)
README
# hast-util-select
[![Build][badge-build-image]][badge-build-url]
[![Coverage][badge-coverage-image]][badge-coverage-url]
[![Downloads][badge-downloads-image]][badge-downloads-url]
[![Size][badge-size-image]][badge-size-url]
[hast][github-hast] utility with equivalents for
`matches`, `querySelector`, and `querySelectorAll`.
## Contents
* [What is this?](#what-is-this)
* [When should I use this?](#when-should-i-use-this)
* [Install](#install)
* [Use](#use)
* [API](#api)
* [`matches(selector, node[, space])`](#matchesselector-node-space)
* [`select(selector, tree[, space])`](#selectselector-tree-space)
* [`selectAll(selector, tree[, space])`](#selectallselector-tree-space)
* [`Space`](#space)
* [Support](#support)
* [Unsupported](#unsupported)
* [Types](#types)
* [Compatibility](#compatibility)
* [Security](#security)
* [Related](#related)
* [Contribute](#contribute)
* [License](#license)
## What is this?
This package lets you find nodes in a tree,
similar to how `matches`,
`querySelector`,
and
`querySelectorAll` work with the DOM.
One notable difference between DOM and hast is that DOM nodes have references
to their parents,
meaning that `document.body.matches(':last-child')` can be evaluated to check
whether the body is the last child of its parent.
This information is not stored in hast,
so selectors like that don’t work.
## When should I use this?
This is a small utility that is quite useful,
but is rather slow if you use it a lot.
For each call,
it has to walk the entire tree.
In some cases,
walking the tree once with
[`unist-util-visit`][github-unist-util-visit]
is smarter,
such as when you want to change certain nodes.
On the other hand,
this is quite powerful and fast enough for many other cases.
This utility is similar to
[`unist-util-select`][github-unist-util-select],
which can find and match any unist node.
## Install
This package is [ESM only][github-gist-esm].
In Node.js (version 16+),
install with [npm][npmjs-install]:
```sh
npm install hast-util-select
```
In Deno with [`esm.sh`][esmsh]:
```js
import {matches, select, selectAll} from 'https://esm.sh/hast-util-select@6'
```
In browsers with [`esm.sh`][esmsh]:
```html
import {matches, select, selectAll} from 'https://esm.sh/hast-util-select@6?bundle'
```
## Use
```js
import {h} from 'hastscript'
import {matches, select, selectAll} from 'hast-util-select'
const tree = h('section', [
h('p', 'Alpha'),
h('p', 'Bravo'),
h('h1', 'Charlie'),
h('p', 'Delta'),
h('p', 'Echo'),
h('p', 'Foxtrot'),
h('p', 'Golf')
])
console.log(matches('section', tree)) // `true`
console.log(select('h1 ~ :nth-child(even)', tree))
// The paragraph with `Delta`
console.log(selectAll('h1 ~ :nth-child(even)', tree))
// The paragraphs with `Delta` and `Foxtrot`
```
## API
This package exports the identifiers [`matches`][api-matches],
[`select`][api-select],
and [`selectAll`][api-select-all].
There is no default export.
### `matches(selector, node[, space])`
Check that the given `node` matches `selector`.
This only checks the element itself,
not the surrounding tree.
Thus,
nesting in selectors is not supported (`p b`, `p > b`),
neither are selectors like `:first-child`,
etc.
This only checks that the given element matches the selector.
###### Parameters
* `selector`
(`string`, example: `'h1'`, `'a, b'`)
— CSS selector
* `node`
([`Node`][github-hast-nodes], optional)
— node that might match `selector`,
should be an element
* `space`
([`Space`][api-space], default: `'html'`)
— name of namespace
###### Returns
Whether `node` matches `selector` (`boolean`).
###### Example
```js
import {h} from 'hastscript'
import {matches} from 'hast-util-select'
matches('b, i', h('b')) // => true
matches(':any-link', h('a')) // => false
matches(':any-link', h('a', {href: '#'})) // => true
matches('.classy', h('a', {className: ['classy']})) // => true
matches('#id', h('a', {id: 'id'})) // => true
matches('[lang|=en]', h('a', {lang: 'en'})) // => true
matches('[lang|=en]', h('a', {lang: 'en-GB'})) // => true
```
### `select(selector, tree[, space])`
Select the first element that matches `selector` in the given `tree`.
Searches the tree in *[preorder][github-unist-preorder]*.
###### Parameters
* `selector`
(`string`, example: `'h1'`, `'a, b'`)
— CSS selector, such as (`h1`, `a, b`)
* `tree`
([`Node`][github-hast-nodes], optional)
— tree to search
* `space`
([`Space`][api-space], default: `'html'`)
— name of namespace
###### Returns
First element in `tree` that matches `selector` or `undefined` if nothing is
found.
This could be `tree` itself.
###### Example
```js
import {h} from 'hastscript'
import {select} from 'hast-util-select'
console.log(
select(
'h1 ~ :nth-child(even)',
h('section', [
h('p', 'Alpha'),
h('p', 'Bravo'),
h('h1', 'Charlie'),
h('p', 'Delta'),
h('p', 'Echo')
])
)
)
```
Yields:
```js
{ type: 'element',
tagName: 'p',
properties: {},
children: [ { type: 'text', value: 'Delta' } ] }
```
### `selectAll(selector, tree[, space])`
Select all elements that match `selector` in the given `tree`.
Searches the tree in *[preorder][github-unist-preorder]*.
###### Parameters
* `selector`
(`string`, example: `'h1'`, `'a, b'`)
— CSS selector
* `tree`
([`Node`][github-hast-nodes], optional)
— tree to search
* `space`
([`Space`][api-space], default: `'html'`)
— name of namespace
###### Returns
Elements in `tree` that match `selector`.
This could include `tree` itself.
###### Example
```js
import {h} from 'hastscript'
import {selectAll} from 'hast-util-select'
console.log(
selectAll(
'h1 ~ :nth-child(even)',
h('section', [
h('p', 'Alpha'),
h('p', 'Bravo'),
h('h1', 'Charlie'),
h('p', 'Delta'),
h('p', 'Echo'),
h('p', 'Foxtrot'),
h('p', 'Golf')
])
)
)
```
Yields:
```js
[ { type: 'element',
tagName: 'p',
properties: {},
children: [ { type: 'text', value: 'Delta' } ] },
{ type: 'element',
tagName: 'p',
properties: {},
children: [ { type: 'text', value: 'Foxtrot' } ] } ]
```
### `Space`
Namespace (TypeScript type).
###### Type
```ts
type Space = 'html' | 'svg'
```
## Support
* [x] `*` (universal selector)
* [x] `,` (multiple selector)
* [x] `p` (type selector)
* [x] `.class` (class selector)
* [x] `#id` (id selector)
* [x] `article p` (combinator: descendant selector)
* [x] `article > p` (combinator: child selector)
* [x] `h1 + p` (combinator: next-sibling selector)
* [x] `h1 ~ p` (combinator: subsequent sibling selector)
* [x] `[attr]` (attribute existence)
* [x] `[attr… i]` (attribute case-insensitive)
* [x] `[attr… s]` (attribute case-sensitive) (useless, default)
* [x] `[attr=value]` (attribute equality)
* [x] `[attr~=value]` (attribute contains in space-separated list)
* [x] `[attr|=value]` (attribute equality or prefix)
* [x] `[attr^=value]` (attribute begins with)
* [x] `[attr$=value]` (attribute ends with)
* [x] `[attr*=value]` (attribute contains)
* [x] `:dir()` (functional pseudo-class)
* [x] `:has()` (functional pseudo-class; also supports `a:has(> b)`)
* [x] `:is()` (functional pseudo-class)
* [x] `:lang()` (functional pseudo-class)
* [x] `:not()` (functional pseudo-class)
* [x] `:any-link` (pseudo-class)
* [x] `:blank` (pseudo-class)
* [x] `:checked` (pseudo-class)
* [x] `:disabled` (pseudo-class)
* [x] `:empty` (pseudo-class)
* [x] `:enabled` (pseudo-class)
* [x] `:optional` (pseudo-class)
* [x] `:read-only` (pseudo-class)
* [x] `:read-write` (pseudo-class)
* [x] `:required` (pseudo-class)
* [x] `:root` (pseudo-class)
* [x] `:scope` (pseudo-class):
* [x] \* `:first-child` (pseudo-class)
* [x] \* `:first-of-type` (pseudo-class)
* [x] \* `:last-child` (pseudo-class)
* [x] \* `:last-of-type` (pseudo-class)
* [x] \* `:only-child` (pseudo-class)
* [x] \* `:only-of-type` (pseudo-class)
* [x] \* `:nth-child()` (functional pseudo-class)
* [x] \* `:nth-last-child()` (functional pseudo-class)
* [x] \* `:nth-last-of-type()` (functional pseudo-class)
* [x] \* `:nth-of-type()` (functional pseudo-class)
## Unsupported
* [ ] † `||` (column combinator)
* [ ] † `ns|E` (namespace type selector)
* [ ] † `*|E` (any namespace type selector)
* [ ] † `|E` (no namespace type selector)
* [ ] † `[ns|attr]` (namespace attribute)
* [ ] † `[*|attr]` (any namespace attribute)
* [ ] † `[|attr]` (no namespace attribute)
* [ ] ‖ `:nth-child(n of S)` (functional pseudo-class, note: scoping to
parents is not supported)
* [ ] ‖ `:nth-last-child(n of S)` (functional pseudo-class, note: scoping to
parents is not supported)
* [ ] † `:active` (pseudo-class)
* [ ] † `:autofill` (pseudo-class)
* [ ] † `:buffering` (pseudo-class)
* [ ] § `:closed` (pseudo-class)
* [ ] † `:current` (pseudo-class)
* [ ] † `:current()` (functional pseudo-class)
* [ ] † `:default` (pseudo-class)
* [ ] † `:defined` (pseudo-class)
* [ ] † `:focus` (pseudo-class)
* [ ] † `:focus-visible` (pseudo-class)
* [ ] † `:focus-within` (pseudo-class)
* [ ] † `:fullscreen` (pseudo-class)
* [ ] † `:future` (pseudo-class)
* [ ] § `:host()` (functional pseudo-class)
* [ ] § `:host-context()` (functional pseudo-class)
* [ ] † `:hover` (pseudo-class)
* [ ] ‡ `:in-range` (pseudo-class)
* [ ] † `:indeterminate` (pseudo-class)
* [ ] ‡ `:invalid` (pseudo-class)
* [ ] † `:link` (pseudo-class)
* [ ] † `:local-link` (pseudo-class)
* [ ] † `:modal` (pseudo-class)
* [ ] † `:muted` (pseudo-class)
* [ ] † `:nth-col()` (functional pseudo-class)
* [ ] † `:nth-last-col()` (functional pseudo-class)
* [ ] § `:open` (pseudo-class)
* [ ] ‡ `:out-of-range` (pseudo-class)
* [ ] † `:past` (pseudo-class)
* [ ] † `:paused` (pseudo-class)
* [ ] † `:placeholder-shown` (pseudo-class)
* [ ] † `:playing` (pseudo-class)
* [ ] † `:seeking` (pseudo-class)
* [ ] † `:stalled` (pseudo-class)
* [ ] † `:target` (pseudo-class)
* [ ] † `:target-within` (pseudo-class)
* [ ] † `:user-invalid` (pseudo-class)
* [ ] ‡ `:valid` (pseudo-class)
* [ ] † `:visited` (pseudo-class)
* [ ] † `:volume-locked` (pseudo-class)
* [ ] § `:where()` (functional pseudo-class)
* [ ] † `::before` (pseudo-elements: none are supported)
###### Notes
* \* — not supported in `matches`
* † — needs a user,
browser,
interactivity,
scripting,
or whole CSS to make sense
* ‡ — not very interested in writing / including the code for this
* § — too new,
the spec is still changing
* ‖ — pr wanted!
* `:any()` and `:matches()` are renamed to `:is()` in CSS.
## Types
This package is fully typed with [TypeScript][].
It exports the additional type [`Space`][api-space].
## 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-select@6`,
compatible with Node.js 16.
## Security
This package does not change the syntax tree so there are no openings for
[cross-site scripting (XSS)][wikipedia-xss] attacks.
## Related
* [`unist-util-select`][github-unist-util-select]
— select unist nodes with CSS-like selectors
* [`hast-util-find-and-replace`](https://github.com/syntax-tree/hast-util-find-and-replace)
— find and replace text in a hast tree
* [`hast-util-parse-selector`](https://github.com/syntax-tree/hast-util-parse-selector)
— create an element from a simple CSS selector
* [`hast-util-from-selector`](https://github.com/syntax-tree/hast-util-from-selector)
— create an element from a complex CSS selector
## Contribute
See [`contributing.md`][health-contributing]
in
[`syntax-tree/.github`][health]
for ways to get started.
See [`support.md`][health-support] for ways to get help.
This project has a [code of conduct][health-coc].
By interacting with this repository,
organization,
or community you agree to abide by its terms.
## License
[MIT][file-license] © [Titus Wormer][wooorm]
[api-matches]: #matchesselector-node-space
[api-select]: #selectselector-tree-space
[api-select-all]: #selectallselector-tree-space
[api-space]: #space
[badge-build-image]: https://github.com/syntax-tree/hast-util-select/workflows/main/badge.svg
[badge-build-url]: https://github.com/syntax-tree/hast-util-select/actions
[badge-coverage-image]: https://img.shields.io/codecov/c/github/syntax-tree/hast-util-select.svg
[badge-coverage-url]: https://codecov.io/github/syntax-tree/hast-util-select
[badge-downloads-image]: https://img.shields.io/npm/dm/hast-util-select.svg
[badge-downloads-url]: https://www.npmjs.com/package/hast-util-select
[badge-size-image]: https://img.shields.io/bundlejs/size/hast-util-select
[badge-size-url]: https://bundlejs.com/?q=hast-util-select
[esmsh]: https://esm.sh
[file-license]: license
[github-gist-esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
[github-hast]: https://github.com/syntax-tree/hast
[github-hast-nodes]: https://github.com/syntax-tree/hast#nodes
[github-unist-preorder]: https://github.com/syntax-tree/unist#preorder
[github-unist-util-select]: https://github.com/syntax-tree/unist-util-select
[github-unist-util-visit]: https://github.com/syntax-tree/unist-util-visit
[health]: https://github.com/syntax-tree/.github
[health-coc]: https://github.com/syntax-tree/.github/blob/main/code-of-conduct.md
[health-contributing]: https://github.com/syntax-tree/.github/blob/main/contributing.md
[health-support]: https://github.com/syntax-tree/.github/blob/main/support.md
[npmjs-install]: https://docs.npmjs.com/cli/install
[typescript]: https://www.typescriptlang.org
[wikipedia-xss]: https://en.wikipedia.org/wiki/Cross-site_scripting
[wooorm]: https://wooorm.com