https://github.com/syntax-tree/hast-util-shift-heading
utility to change heading rank (or depth, level) in hast
https://github.com/syntax-tree/hast-util-shift-heading
hast hast-util heading html shift syntax-tree util
Last synced: 4 months ago
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utility to change heading rank (or depth, level) in hast
- Host: GitHub
- URL: https://github.com/syntax-tree/hast-util-shift-heading
- Owner: syntax-tree
- License: mit
- Created: 2019-03-14T22:48:55.000Z (almost 7 years ago)
- Default Branch: main
- Last Pushed: 2023-08-02T13:28:04.000Z (over 2 years ago)
- Last Synced: 2025-08-09T07:41:54.651Z (6 months ago)
- Topics: hast, hast-util, heading, html, shift, syntax-tree, util
- Language: JavaScript
- Homepage: https://unifiedjs.com
- Size: 70.3 KB
- Stars: 3
- Watchers: 8
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: license
Awesome Lists containing this project
README
# hast-util-shift-heading
[![Build][build-badge]][build]
[![Coverage][coverage-badge]][coverage]
[![Downloads][downloads-badge]][downloads]
[![Size][size-badge]][size]
[![Sponsors][sponsors-badge]][collective]
[![Backers][backers-badge]][collective]
[![Chat][chat-badge]][chat]
[hast][] utility to change ranks (also knows as depth or level) of headings.
## Contents
* [What is this?](#what-is-this)
* [When should I use this?](#when-should-i-use-this)
* [Install](#install)
* [Use](#use)
* [API](#api)
* [`shiftHeading(tree, shift)`](#shiftheadingtree-shift)
* [Types](#types)
* [Compatibility](#compatibility)
* [Security](#security)
* [Related](#related)
* [Contribute](#contribute)
* [License](#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
import {shiftHeading} from 'https://esm.sh/hast-util-shift-heading@4?bundle'
```
## 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.
### `shiftHeading(tree, shift)`
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`](https://github.com/syntax-tree/hast-util-heading)
— check if a node is heading content
* [`hast-util-heading-rank`](https://github.com/syntax-tree/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