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hast-util-from-dom

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hast utility to transform from a DOM tree.

Contents

What is this?

This package is a utility that takes a DOM tree (from the actual DOM or from things like jsdom) as input and turns it into a hast (HTML) syntax tree.

When should I use this?

You can use this project when you want to use hast in browsers. This package is very small, but it does so by:

  • …not providing positional information
  • …potentially yielding varying results in different (especially older) browsers

The hast utility hast-util-to-dom does the inverse of this utility. It turns hast into a DOM tree.

The rehype plugin rehype-dom-parse wraps this utility to parse HTML with DOM APIs.

Install

This package is ESM only. In Node.js (version 16+), install with npm:

npm install hast-util-from-dom

In Deno with esm.sh:

import {fromDom} from 'https://esm.sh/hast-util-from-dom@5'

In browsers with esm.sh:

<script type="module">
  import {fromDom} from 'https://esm.sh/hast-util-from-dom@5?bundle'
</script>

Use

Say our page example.html looks as follows:

<!doctype html>
<title>Example</title>
<body>
  <main>
    <h1>Hi</h1>
    <p><em>Hello</em>, world!</p>
  </main>
  <script type="module">
    import {fromDom} from 'https://esm.sh/hast-util-from-dom@4?bundle'

    const hast = fromDom(document.querySelector('main'))

    console.log(hast)
  </script>

Now running open example.html prints the following to the console:

{type: "element", tagName: "main", properties: {}, children: Array}

API

This package exports the identifier fromDom. There is no default export.

fromDom(tree, options?)

Transform a DOM tree to a hast tree.

Parameters
  • tree (DomNode) — DOM tree to transform
  • options (Options, optional) — configuration
Returns

Equivalent hast node (HastNode).

AfterTransform

Callback called when each node is transformed (TypeScript type).

Parameters
  • domNode (DomNode) — DOM node that was handled
  • hastNode (HastNode) — corresponding hast node
Returns

Nothing.

Options

Configuration (TypeScript type).

Fields
  • afterTransform (AfterTransform, optional) — callback called when each node is transformed
Returns

HastNode.

Types

This package is fully typed with TypeScript. It exports the additional types AfterTransform and Options.

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-from-dom@^5, compatible with Node.js 16.

Security

Use of hast-util-from-dom itself is safe but see other utilities for more information on potential security problems.

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, organisation, or community you agree to abide by its terms.

Related

License

ISC © Keith McKnight