astro-auto-title

A Remark plugin for Astro that automatically adds an <h1> element to markdown using a variable from the frontmatter or vice versa, add the text of <h1> as a variable to frontmatter

Note: This plugin requires Astro version 2.0.0-beta.0 or above

Features

• Automatically add <h1> heading using frontmatter variable
• Copy the text of <h1> to the frontmatter as a variable
• Create dynamic default titles using the documents mdast and vfile
• Option to force only one <h1> per document by removing any extras
• Option to shift extra <h1> headings to a lower depth
• Option to override frontmatter variables defined in file

When do I Use This?

Use this plugin when you have a CMS that enforces a variable in the frontmatter like title but you forget to add a # Heading in the markdown body. This can also be useful when using the getHeadings function from Astro because it can fail if there is no <h1> heading

There are also other useful options like:

• Create dyanmic default titles using the document mdast and vfile if document has nethier a # Heading or frontmatter variable
• Add the text of the documents <h1> to the frontmatter as a variable
• forcing only one <h1> to a document by removing extras or shifting their depth downwards

How to Use

Setup Config:

// astro.config.mjs
import { defineConfig } from 'astro/config';

import { autoTitle } from 'astro-auto-title';

export default defineConfig({
    markdown: { 
        remarkPlugins: [
            [autoTitle, {
                frontmatterToH1: 'title',
                h1ToFrontmatter: 'title',
            }]
        ]
    }
});

These 3 Markdown Files:

// 1
---
title: H1 Heading
---

This is a description

// 2
# H1 Heading

This is a description

// 3
---
title: I dont override existing h1
---
# H1 Heading

This is a description

Are rendered into this HTML:

<h1>H1 Heading</h1>
<p>This is a description</p>

Options

Defaults

{
    frontmatterToH1: 'title',
    h1ToFrontmatter: 'title',
    defaultText: (mdast, vfile) => (
        // Tries to return a string similar to Astro.url.pathname
        // assumes your .md is located in src/pages
        vfile.history
            .pop()
            ?.replace(vfile.cwd, '')
            .replace(/(\/\/)|(\\)+/g, '/')
            .replace('/src/pages','')
            .replace('/index.md', '')
            .replace('.md', '')
    ),
    override: false,
    trimExtraH1: true,
    shiftExtraH1: false
}

frontmatterToH1?: string|false

Default: title

If no <h1> is found in document inject one with the text of this frontmatter variable

If false is passed it uses the text defined in default

Example:

{
    frontmatterToH1: 'title'
}

---
title: H1 Heading
---

This is a description

<h1>H1 Heading</h1>
<p>This is a description</p>

h1ToFrontmatter?: string|false

Default: title

This variable is added to frontmatter containing the first <h1> element's text

If false is passed no variable is added to frontmatter

Example:

{
    h1ToFrontmatter: 'title'
}

# Heading defined in file

This is a description

frontmatter = {
    title: 'Heading defined in file'
}

defaultText?: string | (MDAST, VFile) => string

Default

(mdast, vfile) => (
    // Tries to return a string similar to Astro.url.pathname
    // assumes your .md is located in src/pages
    vfile.history
        .pop()
        ?.replace(vfile.cwd, '')
        .replace(/(\/\/)|(\\)+/g, '/')
        .replace('/src/pages','')
        .replace('/index.md', '')
        .replace('.md', '')
)

Can be a static string or a function that calculates a default string using the documents mdast tree and vfile

override?: boolean

Default: false

Option to override frontmatter variable if one is already defined in file

trimExtraH1?: boolean

Default: true

Enforces only one <h1> per document, keeps the first <h1> and removes all extras

Example:

# First h1
# Second h1
# Third h1

<h1>First h1</h1>

shiftExtraH1?: 2-6|boolean

Default: false

Note: trimExtraH1 must be set to false to use

Enforces only one <h1> per document by keeping the first <h1> and shifting all extra <h1> elements downwards to defined depth

Passing true shifts extra <h1> elements to <h2>

Passing false stops shifting from happening

Example:

{
    trimExtraH1: false,
    shiftExtraH1: 3
}

# First h1
# Second h1
# Third h1

<h1>First h1</h1>
<h3>Second h1</h3>
<h3>Third h1</h3>