hast utility to check if a node is a (certain) element
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[hast][] utility to check if a node is a (certain) element.
* What is this?
* When should I use this?
* Install
* Use
* API
* [isElement(element[, test[, index, parent[, context]]])](#iselementelement-test-index-parent-context)
* convertElement(test)
* Check
* Test
* TestFunction
* Types
* Compatibility
* Security
* Related
* Contribute
* License
This package is a small utility that checks that a node is a certain element.
Use this small utility if you find yourself repeating code for checking what
elements nodes are.
A similar package, [unist-util-is][unist-util-is], works on any unist node.
For more advanced tests, [hast-util-select][hast-util-select] can be used
to match against CSS selectors.
This package is [ESM only][esm].
In Node.js (version 16+), install with [npm][]:
``sh`
npm install hast-util-is-element
In Deno with [esm.sh][esmsh]:
`js`
import {isElement} from 'https://esm.sh/hast-util-is-element@3'
In browsers with [esm.sh][esmsh]:
`html`
`js
import {isElement} from 'hast-util-is-element'
isElement({type: 'text', value: 'foo'}) // => false
isElement({type: 'element', tagName: 'a', properties: {}, children: []}) // => true
isElement({type: 'element', tagName: 'a', properties: {}, children: []}, 'a') // => true
isElement({type: 'element', tagName: 'a', properties: {}, children: []}, 'b') // => false
isElement({type: 'element', tagName: 'a', properties: {}, children: []}, ['a', 'area']) // => true
`
This package exports the identifiers
[convertElement][api-convert-element] andisElement
[][api-is-element].
There is no default export.
Check if element is an Element and whether it passes the given test.
###### Parameters
* element (unknown, optional)Node
— thing to check, typically [][hast-node]test
* ([Test][api-test], optional)index
— check for a specific element
* (number, optional)element
— position of in its parentparent
* ([Parent][hast-parent], optional)element
— parent of context
* (unknown, optional)this
— context object () to call test with
###### Returns
Whether element is an Element and passes a test (boolean).
###### Throws
When an incorrect test, index, or parent is given.element
There is no error thrown when is not a node or not an element.
Generate a check from a test.
Useful if you’re going to test many nodes, for example when creating a
utility where something else passes a compatible test.
The created function is a bit faster because it expects valid input only:
a element, index, and parent.
###### Parameters
* test ([Test][api-test], optional)
— a test for a specific element
###### Returns
A check ([Check][api-check]).
Check that an arbitrary value is an element (TypeScript type).
###### Parameters
* this (unknown, optional)this
— context object () to call test withelement
* (unknown)index
— anything (typically an element)
* (number, optional)element
— position of in its parentparent
* ([Parent][hast-parent], optional)element
— parent of
###### Returns
Whether this is an element and passes a test (boolean).
Check for an arbitrary element (TypeScript type).
* when string, checks that the element has that tag namefunction
* when , see [TestFunction][api-test-function]Array
* when , checks if one of the subtests pass
###### Type
`ts`
type Test =
| Array
| TestFunction
| string
| null
| undefined
Check if an element passes a test (TypeScript type).
###### Parameters
* element ([Element][hast-element])index
— an element
* (number or undefined)element
— position of in its parentparent
* ([Parent][hast-parent] or undefined)element
— parent of
###### Returns
Whether this element passes the test (boolean, optional).
This package is fully typed with [TypeScript][].
It exports the additional types [Check][api-check],Test
[][api-test], andTestFunction
[][api-test-function].
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-is-element@^3,
compatible with Node.js 16.
hast-util-is-element does not change the syntax tree so there are no openings
for [cross-site scripting (XSS)][xss] attacks.
* hast-util-has-property
— check if a node has a property
* hast-util-is-body-ok-link
— check if a node is “Body OK” link element
* hast-util-is-conditional-comment
— check if a node is a conditional comment
* hast-util-is-css-link
— check if a node is a CSS link element
* hast-util-is-css-style
— check if a node is a CSS style element
* hast-util-embedded
— check if a node is an embedded element
* hast-util-heading
— check if a node is a heading element
* hast-util-interactive
— check if a node is interactive
* hast-util-is-javascript
— check if a node is a JavaScript script element
* hast-util-labelable
— check whether a node is labelable
* hast-util-phrasing
— check if a node is phrasing content
* hast-util-script-supporting
— check if a node is a script-supporting element
* hast-util-sectioning
— check if a node is a sectioning element
* hast-util-transparent
— check if a node is a transparent element
* hast-util-whitespace
— check if a node is inter-element whitespace
See [contributing.md][contributing] in [syntax-tree/.github][health] forsupport.md`][support] for ways to get help.
ways to get started.
See [
This project has a [code of conduct][coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.
[MIT][license] © [Titus Wormer][author]
[build-badge]: https://github.com/syntax-tree/hast-util-is-element/workflows/main/badge.svg
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[downloads]: https://www.npmjs.com/package/hast-util-is-element
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[sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg
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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
[hast-node]: https://github.com/syntax-tree/hast#nodes
[hast-parent]: https://github.com/syntax-tree/hast#parent
[hast-element]: https://github.com/syntax-tree/hast#element
[xss]: https://en.wikipedia.org/wiki/Cross-site_scripting
[unist-util-is]: https://github.com/syntax-tree/unist-util-is
[hast-util-select]: https://github.com/syntax-tree/hast-util-select
[api-is-element]: #iselementelement-test-index-parent-context
[api-convert-element]: #convertelementtest
[api-check]: #check
[api-test]: #test
[api-test-function]: #testfunction