retext-readability

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[retext][] plugin to check readability.

Contents

* What is this?
* When should I use this?
* Install
* Use
* API
* [unified().use(retextReadability[, options])](#unifieduseretextreadability-options)
* Options
* Messages
* Types
* Compatibility
* Related
* Contribute
* License

What is this?

This package is a [unified][] ([retext][]) plugin to check readability: whether
your presumed target audience can read your prose.
It applies [Dale—Chall][dale-chall],
[Automated Readability][automated-readability], [Coleman-Liau][], [Flesch][],
[Gunning-Fog][], [SMOG][], and [Spache][].

When should I use this?

You can use this plugin when you’re dealing with content that might be
difficult to read to some folks, and have authors that can fix that content.

> 💡 Tip: I also made an online, editable, demo, similar to this project:
> wooorm.com/readability.

Install

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

``sh
npm install retext-readability
`

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

`js
import retextReadability from 'https://esm.sh/retext-readability@8'
`

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

`html

`

Use

Say our document example.txt contains:

`txt
The cat sat on the mat

The constellation also contains an isolated neutron
star—Calvera—and H1504+65, the hottest white dwarf yet
discovered, with a surface temperature of 200,000 kelvin
`

…and our module example.js contains:

`js
import retextEnglish from 'retext-english'
import retextReadability from 'retext-readability'
import retextStringify from 'retext-stringify'
import {read} from 'to-vfile'
import {unified} from 'unified'
import {reporter} from 'vfile-reporter'

const file = await unified()
.use(retextEnglish)
.use(retextReadability)
.use(retextStringify)
.process(await read('example.txt'))

console.error(reporter(file))
`

…then running node example.js yields:

`txt
example.txt
3:1-5:57 warning Unexpected hard to read sentence, according to 4 out of 7 algorithms readability retext-readability

⚠ 1 warning
`

The default target age is 16.
You can pass something else, such as 6:

`diff
.use(retextEnglish)
- .use(retextReadability)
+ .use(retextReadability, {age: 6})
.use(retextStringify)
`

…then running node example.js again yields:

`txt
example.txt
1:1-1:23 warning Unexpected hard to read sentence, according to 4 out of 7 algorithms readability retext-readability
3:1-5:57 warning Unexpected hard to read sentence, according to all 7 algorithms readability retext-readability

⚠ 2 warnings
`

API

This package exports no identifiers.
The default export is [retextReadability][api-retext-readability].

$3

Check hard to read sentences.

###### Parameters

* options ([Options][api-options], optional)
— configuration

###### Returns

Transform ([Transformer][unified-transformer]).

$3

Configuration (TypeScript type).

###### Fields

* age (number, default: 16)
— target age group
* minWords (number, default: 5)
— check sentences with at least this number of words;
most algos are made to detect the reading level on an entire text;
this plugin checks each sentence on its own;
for short sentences, one long or complex word can strongly skew the
results
* threshold (number, default: 4 / 7)
— number of algos (out of 7) that need to agree something is hard to read

Messages

Each message is emitted as a [VFileMessage][vfile-message], with source set
to 'retext-readability', ruleId to 'readability', actual to the
difficult sentence, and expected to an empty array.

Types

This package is fully typed with [TypeScript][].
It exports the additional type [Options][api-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, retext-readability@^8,
compatible with Node.js 16.

Related

* retext-syntax-mentions
— classify @mentions as syntax
* retext-syntax-urls
— classify URLs and filepaths as syntax
* retext-simplify
— check phrases for simpler alternatives

Contribute

See [contributing.md][contributing] in [retextjs/.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/retextjs/retext-readability/workflows/main/badge.svg

[build]: https://github.com/retextjs/retext-readability/actions

[coverage-badge]: https://img.shields.io/codecov/c/github/retextjs/retext-readability.svg

[coverage]: https://codecov.io/github/retextjs/retext-readability

[downloads-badge]: https://img.shields.io/npm/dm/retext-readability.svg

[downloads]: https://www.npmjs.com/package/retext-readability

[size-badge]: https://img.shields.io/bundlejs/size/retext-readability

[size]: https://bundlejs.com/?q=retext-readability

[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/retextjs/retext/discussions

[npm]: https://docs.npmjs.com/cli/install

[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c

[esmsh]: https://esm.sh

[typescript]: https://www.typescriptlang.org

[health]: https://github.com/retextjs/.github

[contributing]: https://github.com/retextjs/.github/blob/main/contributing.md

[support]: https://github.com/retextjs/.github/blob/main/support.md

[coc]: https://github.com/retextjs/.github/blob/main/code-of-conduct.md

[license]: license

[author]: https://wooorm.com

[automated-readability]: https://github.com/words/automated-readability

[coleman-liau]: https://github.com/words/coleman-liau

[dale-chall]: https://github.com/words/dale-chall-formula

[flesch]: https://github.com/words/flesch

[gunning-fog]: https://github.com/words/gunning-fog

[retext]: https://github.com/retextjs/retext

[smog]: https://github.com/words/smog-formula

[spache]: https://github.com/words/spache-formula

[unified]: https://github.com/unifiedjs/unified

[unified-transformer]: https://github.com/unifiedjs/unified#transformer

[vfile-message]: https://github.com/vfile/vfile-message

[api-options]: #options

[api-retext-readability]: #unifieduseretextreadability-options