hast-util-shift-heading

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[hast][] utility to change ranks (also knows as depth or level) of headings.

Contents

* What is this?
* When should I use this?
* Install
* Use
* API
* shiftHeading(tree, shift)
* Types
* Compatibility
* Security
* Related
* Contribute
* License

What is this?

This package is a small utility that rewrites heading ranks relative to a
number.

When should I use this?

You can use this package when you have some content, say an article that starts
with an h1, but want to display it on a page that uses for example an h1
already as the website name (logo?).

You can use the package [hast-util-heading-rank][hast-util-heading-rank]
to get the rank of an element.

Install

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

``sh
npm install hast-util-shift-heading
`

In Deno with [esm.sh][esmsh]:

`js
import {shiftHeading} from 'https://esm.sh/hast-util-shift-heading@4'
`

In browsers with [esm.sh][esmsh]:

`html

`

Use

`js
import {h} from 'hastscript'
import {shiftHeading} from 'hast-util-shift-heading'

const tree = h('main', [
h('h1', 'Alpha'),
h('p', 'Bravo'),
h('h2', 'Charlie'),
h('p', 'Delta'),
h('h5', 'Echo'),
h('p', 'Foxtrot'),
h('h6', 'Golf')
])

shiftHeading(tree, -1)

console.log(tree)
`

Yields:

`js
{ type: 'element',
tagName: 'main',
properties: {},
children:
[ { type: 'element',
tagName: 'h1',
properties: {},
children: [Array] },
{ type: 'element',
tagName: 'p',
properties: {},
children: [Array] },
{ type: 'element',
tagName: 'h1',
properties: {},
children: [Array] },
{ type: 'element',
tagName: 'p',
properties: {},
children: [Array] },
{ type: 'element',
tagName: 'h4',
properties: {},
children: [Array] },
{ type: 'element',
tagName: 'p',
properties: {},
children: [Array] },
{ type: 'element',
tagName: 'h5',
properties: {},
children: [Array] } ] }
`

API

This package exports the identifier [shiftHeading][api-shift-heading].
There is no default export.

$3

Change the rank of all headings (h1 to h6) in tree.

Mutates the tree.
Caps the rank so that shifting would not create invalid headings (so no h0 or
h7).

###### Parameters

* tree ([Node][node]) — tree to change
* shift (number) — non-null finite integer to use to shift ranks

###### Returns

Nothing (undefined).

###### Throws

When shift is not a valid non-null finite integer.

Types

This package is fully typed with [TypeScript][].
It exports no additional types.

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-shift-heading@^4, compatible with Node.js 16.

Security

hast-util-shift-heading changes the syntax tree but can only generated
headings from h1 through h6.
There are no openings for [cross-site scripting (XSS)][xss] attacks.

Related

* hast-util-heading
— check if a node is heading content
* hast-util-heading-rank
— get the rank (or depth, level) of headings

Contribute

See [contributing.md][contributing] in [syntax-tree/.github][health] for
ways to get started.
See [support.md`][support] for ways to get help.

This project has a [code of conduct][coc].
By interacting with this repository, organization, or community you agree to
abide by its terms.

License

[MIT][license] © [Titus Wormer][author]

[build-badge]: https://github.com/syntax-tree/hast-util-shift-heading/workflows/main/badge.svg

[build]: https://github.com/syntax-tree/hast-util-shift-heading/actions

[coverage-badge]: https://img.shields.io/codecov/c/github/syntax-tree/hast-util-shift-heading.svg

[coverage]: https://codecov.io/github/syntax-tree/hast-util-shift-heading

[downloads-badge]: https://img.shields.io/npm/dm/hast-util-shift-heading.svg

[downloads]: https://www.npmjs.com/package/hast-util-shift-heading

[size-badge]: https://img.shields.io/badge/dynamic/json?label=minzipped%20size&query=$.size.compressedSize&url=https://deno.bundlejs.com/?q=hast-util-shift-heading

[size]: https://bundlejs.com/?q=hast-util-shift-heading

[sponsors-badge]: https://opencollective.com/unified/sponsors/badge.svg

[backers-badge]: https://opencollective.com/unified/backers/badge.svg

[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

[node]: https://github.com/syntax-tree/hast#nodes

[hast-util-heading-rank]: https://github.com/syntax-tree/hast-util-heading-rank

[xss]: https://en.wikipedia.org/wiki/Cross-site_scripting

[api-shift-heading]: #shiftheadingtree-shift