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Project: syntax-tree/hast-util-select

Package: hast-util-select@5.0.1

  1. Dependents: 41
  2. hast utility for querySelector, querySelectorAll, and matches
  1. util 143
  2. utility 139
  3. unist 126
  4. html 122
  5. hast 71
  6. hast-util 46
  7. css 9
  8. selector 4
  9. select 2
  10. match 2
  11. matches 2

hast-util-select

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hast utility with equivalents querySelector, querySelectorAll, and matches.

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. This information is not stored in hast, so selectors like that don’t work.

View the list of supported selectors »

Install

This package is ESM only: Node 12+ is needed to use it and it must be imported instead of required.

npm:

npm install hast-util-select

API

This package exports the following identifiers: matches, select, and selectAll. There is no default export.

matches(selector, node[, space])

Check that the given node matches selector. Returns boolean, whether the node matches or not.

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.

Use
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
// ...
Parameters
Returns

boolean — Whether the node matches the selector.

select(selector, tree[, space])

Select the first node matching selector in the given tree (could be the tree itself). Searches the tree in preorder.

Use
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:

{ type: 'element',
  tagName: 'p',
  properties: {},
  children: [ { type: 'text', value: 'Delta' } ] }
Parameters
Returns

Element? — The found element, if any.

selectAll(selector, tree[, space])

Select all nodes matching selector in the given tree (could include the tree itself). Searches the tree in preorder.

Use
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:

[ { type: 'element',
    tagName: 'p',
    properties: {},
    children: [ { type: 'text', value: 'Delta' } ] },
  { type: 'element',
    tagName: 'p',
    properties: {},
    children: [ { type: 'text', value: 'Foxtrot' } ] } ]
Parameters
Returns

Array.<Element> — All found elements, if any.

Support

Unsupported

Notes

Security

hast-util-select does not change the syntax tree so there are no openings for cross-site scripting (XSS) attacks.

Contribute

See contributing.md in syntax-tree/.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.

License

MIT © Titus Wormer