Unified-infer-git-meta NPM

unified-infer-git-meta

unified plugin to infer file metadata from Git of a document.

What is this?

This package is a unified plugin to infer when content was first published, last modified, and who contributed to it, from Git.

unified is a project that transforms content with abstract syntax trees (ASTs). vfile is the virtual file interface used in unified. This is a unified plugin that extracts metadata from Git and exposes it on the vfile.

When should I use this?

This plugin is particularly useful in combination with rehype-meta. When both are used together, output such as the following is generated:

<meta name="copyright" content="© 2019 Jane">
<meta name="author" content="Jane">
<!-- … -->
<meta property="article:published_time" content="2019-12-02T10:00:00.000Z">
<meta property="article:modified_time" content="2019-12-03T19:13:00.000Z">

The downside is that Git might be sparesely cloned when building a website, meaning that only the last commit is available, which means that this plugin cannot find all data.

Install

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

npm install unified-infer-git-meta

In Deno with esm.sh:

import unifiedInferGitMeta from 'https://esm.sh/unified-infer-git-meta@2'

In browsers with esm.sh:

<script type="module">
  import unifiedInferGitMeta from 'https://esm.sh/unified-infer-git-meta@2?bundle'
</script>

Use

Say our module example.js looks as follows:

import rehypeDocument from 'rehype-document'
import rehypeFormat from 'rehype-format'
import rehypeMeta from 'rehype-meta'
import rehypeStringify from 'rehype-stringify'
import remarkParse from 'remark-parse'
import remarkRehype from 'remark-rehype'
import {read} from 'to-vfile'
import {unified} from 'unified'
import unifiedInferGitMeta from 'unified-infer-git-meta'

const file = await unified()
  .use(remarkParse)
  .use(unifiedInferGitMeta)
  .use(remarkRehype)
  .use(rehypeDocument)
  .use(rehypeMeta, {
    // Published and modified are only added if these two are also defined:
    og: true,
    type: 'article'
  })
  .use(rehypeFormat)
  .use(rehypeStringify)
  .process(await read('readme.md'))

console.log(file.data)
console.log(String(file))

…now running node example.js yields:

{
  meta: {
    author: 'Titus Wormer',
    modified: new Date('2023-08-24T10:13:50.000Z'),
    published: new Date('2021-09-09T11:22:32.000Z')
  }
}

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>readme</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta name="author" content="Titus Wormer">
    <meta property="og:type" content="article">
    <meta property="article:published_time" content="2021-09-09T11:22:32.000Z">
    <meta property="article:modified_time" content="2023-08-24T10:13:50.000Z">
  </head>
  …

API

This package exports no identifiers. The default export is unifiedInferGitMeta.

`unified().use(unifiedInferGitMeta, options?)`

Plugin to infer some meta from Git.

This plugin sets file.data.meta.published to the date a file was first committed, file.data.meta.modified to the date a file was last committed, and file.data.meta.author to an abbreviated list of top authors of the file.

Parameters

options (Options, optional) — configuration

Returns

Transform (Transformer).

`Format`

Format function (TypeScript type).

Parameters

authors (Iterable<string>) — list of authors

Returns

Formatted authors (string).

`Options`

Configuration (TypeScript type).

Fields

authorRest (string, default: 'others') — text to use to label more authors when abbreviating
format (Format, default: format of Intl.ListFormat(locales)) — alternative format function to use; if the authors had to be abbreviated, the last author is instead replaced by authorRest; set limit: -1 to receive all author names
limit (number, default: 3) — max number of authors to include; set to -1 to not limit authors
locales (Array<string> or string, default: 'en') — locale(s) to use to join authors and sort their names

Types

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

It also registers the file.data.meta fields with vfile. If you’re working with the file, make sure to import this plugin somewhere in your types, as that registers the new fields on the file.

/**
 * @typedef {import('unified-infer-git-meta')}
 */

import {VFile} from 'vfile'

const file = new VFile()

console.log(file.data.meta.published) //=> TS now knows that this is a `Date?`.

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, unified-infer-git-meta@^2, compatible with Node.js 16.

rehype-meta — add metadata to the head of a document
rehype-infer-title-meta — infer file metadata from the title of a document
rehype-infer-description-meta — infer file metadata from the description of a document
rehype-infer-reading-time-meta — infer file metadata from the reading time of a document