hast-util-is-element

What is hast-util-is-element?

The hast-util-is-element package is a utility for working with HAST (Hypertext Abstract Syntax Tree) nodes. It provides functions to check if a node is an element and optionally matches a given tag name. This is particularly useful when manipulating or inspecting HTML represented within JavaScript.

What are hast-util-is-element's main functionalities?

Check if a node is an element

This feature allows you to verify if a given node is an element node within a HAST structure. It's useful for filtering or processing nodes in a tree.

const isElement = require('hast-util-is-element');

const node = {type: 'element', tagName: 'div'};
console.log(isElement(node)); // Outputs: true

Check if a node is a specific element

This feature extends the basic check to allow for specification of the tag name. It's useful for finding or working with specific types of elements in a document.

const isElement = require('hast-util-is-element');

const node = {type: 'element', tagName: 'span'};
console.log(isElement(node, 'span')); // Outputs: true

Other packages similar to hast-util-is-element

unist-util-is

This package offers a more generalized approach for checking node types in unist trees, which is a part of the broader unified ecosystem. Unlike hast-util-is-element, unist-util-is can be used with different syntax trees beyond HTML, offering greater flexibility.

hast-util-has-property

Similar in utility scope within the HAST ecosystem, this package checks for the presence of properties in elements. While hast-util-is-element focuses on the type and tag name of nodes, hast-util-has-property deals with the properties of those nodes, providing a complementary functionality.

README

hast-util-is-element

hast utility to check if a node is a (certain) element.

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-is-element

Use

import {isElement} from 'hast-util-is-element'

isElement({type: 'text', value: 'foo'}) // => false

isElement({type: 'element', tagName: 'a'}, 'a') // => true

isElement({type: 'element', tagName: 'a'}, ['a', 'area']) // => true

API

This package exports the following identifiers: isElement, convertElement. There is no default export.

isElement(node[, test[, index, parent[, context]]])

Check if the given value is a (certain) element.

• node (Node) — Node to check.
• test (Function, string, or Array.<Test>, optional) — When array, checks if any one of the subtests pass. When string, checks that the element has that tag name. When function, see test
• index (number, optional) — Index of node in parent
• parent (Node, optional) — Parent of node
• context (*, optional) — Context object to invoke test with

Returns

boolean — Whether test passed and node is an Element.

Throws

Error — When an incorrect test, index, or parent is given. A node that is not a node, or not an element, does not throw.

function test(element[, index, parent])

Parameters

• element (Element) — Element to check
• index (number?) — Index of node in parent
• parent (Node?) — Parent of node

Context

* — The to is given context.

Returns

boolean? — Whether element matches.

convertElement(test)

Create a test function from test, that can later be called with a node, index, and parent. 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 slightly faster because it expects valid input only. Therefore, passing invalid input, yields unexpected results.

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 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

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