$ gnpm install hast-util-is-element
hast-util-is-element
hast utility to check if a node is a (certain) element.
Contents
- What is this?
- When should I use this?
- Install
- Use
- API
- Types
- Compatibility
- Security
- Related
- Contribute
- License
What is this?
This package is a small utility that checks that a node is a certain element.
When should I use this?
Use this small utility if you find yourself repeating code for checking what elements nodes are.
A similar package, unist-util-is, works on any unist node.
For more advanced tests, hast-util-select can be used
to match against CSS selectors.
Install
This package is ESM only. In Node.js (version 14.14+ and 16.0+), install with npm:
npm install hast-util-is-element
In Deno with esm.sh:
import {isElement} from 'https://esm.sh/hast-util-is-element@2'
In browsers with esm.sh:
<script type="module">
import {isElement} from 'https://esm.sh/hast-util-is-element@2?bundle'
</script>
Use
import {isElement} from 'hast-util-is-element'
isElement({type: 'text', value: 'foo'}) // => false
isElement({type: 'element', tagName: 'a'}) // => true
isElement({type: 'element', tagName: 'a'}, 'a') // => true
isElement({type: 'element', tagName: 'a'}, ['a', 'area']) // => true
API
This package exports the identifiers isElement and
convertElement.
There is no default export.
isElement(node[, test[, index, parent[, context]]])
Check if node is an Element and whether it passes the given test.
Parameters
node(unknown) — thing to check, typicallyNodetest(TestorPredicateTest, optional) — a check for a specific elementindex(number, optional) — the node’s position in its parentparent(Node, optional) — the node’s parentcontext(any, optional) — context object (this) to calltestwith
Returns
Whether node is an Element and passes a test (boolean).
Throws
When an incorrect test, index, or parent is given.
There is no error thrown when node is not a node or not an element.
convertElement(test)
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 node, index, and parent.
Parameters
test(TestorPredicateTest, optional) — a check for a specific element
Returns
An assertion (AssertAnything or
AssertPredicate).
AssertAnything
Check that an arbitrary value is an element, unaware of TypeScript inferral (TypeScript type).
Parameters
node(unknown) — anything (typically a node)index(number, optional) — the node’s position in its parentparent(Node, optional) — the node’s parent
Returns
Whether this is an element and passes a test (boolean).
AssertPredicate
Check that an arbitrary value is a specific element, aware of TypeScript (TypeScript type).
Type parameters
T(Element) — element type
Parameters
node(unknown) — anything (typically a node)index(number, optional) — the node’s position in its parentparent(Node, optional) — the node’s parent
Returns
Whether this is an element and passes a test (node is T).
Test
Check for an arbitrary element, unaware of TypeScript inferral (TypeScript type).
Type
type Test = null | undefined | string | TestFunctionAnything | Array<string | TestFunctionAnything>
Checks that the given thing is an element, and then:
- when
string, checks that the element has that tag name - when
function, seeTestFunctionAnything - when
Array, checks if one of the subtests pass
TestFunctionAnything
Check if an element passes a test, unaware of TypeScript inferral (TypeScript type).
Parameters
element(Element) — an elementindex(number, optional) — the element’s position in its parentparent(Node, optional) — the element’s parent
Returns
Whether this element passes the test (boolean).
PredicateTest
Check for an element that can be inferred by TypeScript (TypeScript type).
Type
type PredicateTest<T extends Element> =
| T['tagName']
| TestFunctionPredicate<T>
| Array<T['tagName'] | TestFunctionPredicate<T>>
TestFunctionPredicate
Check if an element passes a certain node test (TypeScript type).
Type parameters
T(Element) — element type
Parameters
element(Element) — an elementindex(number, optional) — the element’s position in its parentparent(Node, optional) — the element’s parent
Returns
Whether this element passes the test (element is T).
Types
This package is fully typed with TypeScript.
It exports the additional types AssertAnything,
AssertPredicate, Test,
TestFunctionAnything,
TestFunctionPredicate, and
PredicateTest.
Compatibility
Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.
Security
hast-util-is-element does not change the syntax tree so there are no openings
for cross-site scripting (XSS) attacks.
Related
hast-util-has-property— check if a node has a propertyhast-util-is-body-ok-link— check if a node is “Body OK” link elementhast-util-is-conditional-comment— check if a node is a conditional commenthast-util-is-css-link— check if a node is a CSS link elementhast-util-is-css-style— check if a node is a CSS style elementhast-util-embedded— check if a node is an embedded elementhast-util-heading— check if a node is a heading elementhast-util-interactive— check if a node is interactivehast-util-is-javascript— check if a node is a JavaScript script elementhast-util-labelable— check whether a node is labelablehast-util-phrasing— check if a node is phrasing contenthast-util-script-supporting— check if a node is a script-supporting elementhast-util-sectioning— check if a node is a sectioning elementhast-util-transparent— check if a node is a transparent elementhast-util-whitespace— check if a node is inter-element whitespace
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
Current Tags
- 2.1.3 ... latest (3 years ago)
12 Versions
- @types/hast ^2.0.0
- @types/unist ^2.0.0
- @types/node ^18.0.0
- c8 ^7.0.0
- prettier ^2.0.0
- remark-cli ^11.0.0
- remark-preset-wooorm ^9.0.0
- tsd ^0.25.0
- type-coverage ^2.0.0
- typescript ^4.0.0
- unified ^10.0.0
- xo ^0.53.0