hast-util-from-parse5

hast utility to transform from parse5s AST.

What is this?
When should I use this?
Install
Use
API
Types
Compatibility
Security
Related
Contribute
License

What is this?

This package is a utility that can turn a parse5 tree into a hast tree.

When should I use this?

You can use this package when using parse5 as an HTML parser and wanting to work with hast.

The utility hast-util-to-parse5 does the inverse of this utility. It generates parse5s AST again.

The utility hast-util-from-html wraps this utility and parse5 to both parse HTML and generate hast from it.

Install

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

npm install hast-util-from-parse5

In Deno with esm.sh:

import {fromParse5} from "https://esm.sh/hast-util-from-parse5@8"

In browsers with esm.sh:

<script type="module">
  import {fromParse5} from "https://esm.sh/hast-util-from-parse5@8?bundle"
</script>

Use

Say our document example.html contains:

<!doctype html><title>Hello!</title><h1 id="world">World!<!--after-->

…and our module example.js looks as follows:

import {fromParse5} from 'hast-util-from-parse5'
import {parse} from 'parse5'
import {read} from 'to-vfile'
import {inspect} from 'unist-util-inspect'

const file = await read('example.html')
const p5ast = parse(String(file), {sourceCodeLocationInfo: true})
const hast = fromParse5(p5ast, {file})

console.log(inspect(hast))

…now running node example.js yields:

root[2] (1:1-2:1, 0-70)
│ data: {"quirksMode":false}
├─0 doctype (1:1-1:16, 0-15)
└─1 element<html>[2]
    │ properties: {}
    ├─0 element<head>[1]
    │   │ properties: {}
    │   └─0 element<title>[1] (1:16-1:37, 15-36)
    │       │ properties: {}
    │       └─0 text "Hello!" (1:23-1:29, 22-28)
    └─1 element<body>[1]
        │ properties: {}
        └─0 element<h1>[3] (1:37-2:1, 36-70)
            │ properties: {"id":"world"}
            ├─0 text "World!" (1:52-1:58, 51-57)
            ├─1 comment "after" (1:58-1:70, 57-69)
            └─2 text "\n" (1:70-2:1, 69-70)

API

This package exports the identifier fromParse5. There is no default export.

`fromParse5(tree[, options])`

Transform a parse5 AST to hast.

Parameters

tree (Parse5Node) — parse5 tree to transform
options (Options, optional) — configuration

Returns

hast tree (HastNode).

`Options`

Configuration (TypeScript type).

Fields

`file`

File used to add positional info to nodes (VFile, optional).

If given, the file should represent the original HTML source.

`space`

Which space the document is in (Space, default: 'html').

When an <svg> element is found in the HTML space, this package already automatically switches to and from the SVG space when entering and exiting it.

`verbose`

Whether to add extra positional info about starting tags, closing tags, and attributes to elements (boolean, default: false).

👉 Note: only used when file is given.

For the following HTML:

<img src="http://example.com/fav.ico" alt="foo" title="bar">

The verbose info would looks as follows:

{
  type: 'element',
  tagName: 'img',
  properties: {src: 'http://example.com/fav.ico', alt: 'foo', title: 'bar'},
  children: [],
  data: {
    position: {
      opening: {
        start: {line: 1, column: 1, offset: 0},
        end: {line: 1, column: 61, offset: 60}
      },
      closing: null,
      properties: {
        src: {
          start: {line: 1, column: 6, offset: 5},
          end: {line: 1, column: 38, offset: 37}
        },
        alt: {
          start: {line: 1, column: 39, offset: 38},
          end: {line: 1, column: 48, offset: 47}
        },
        title: {
          start: {line: 1, column: 49, offset: 48},
          end: {line: 1, column: 60, offset: 59}
        }
      }
    }
  },
  position: {
    start: {line: 1, column: 1, offset: 0},
    end: {line: 1, column: 61, offset: 60}
  }
}

`Space`

Namespace (TypeScript type).

Type

type Space = 'html' | 'svg'

Types

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

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-parse5@^8, compatible with Node.js 16.

Security

Use of hast-util-from-parse5 can open you up to a cross-site scripting (XSS) attack if Parse5’s AST is unsafe.

hast-util-to-parse5 — transform hast to Parse5’s AST
hast-util-to-nlcst — transform hast to nlcst
hast-util-to-mdast — transform hast to mdast
hast-util-to-xast — transform hast to xast
mdast-util-to-hast — transform mdast to hast
mdast-util-to-nlcst — transform mdast to nlcst

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.