README.md

marked-gfm-heading-id

Add ids to headings like GitHub.

Usage

import { marked } from "marked";
import { gfmHeadingId } from "marked-gfm-heading-id";

// or UMD script
// <script src="https://cdn.jsdelivr.net/npm/marked/lib/marked.umd.js"></script>
// <script src="https://cdn.jsdelivr.net/npm/marked-gfm-heading-id/lib/index.umd.js"></script>

const options = {
	prefix: "my-prefix-",
};

marked.use(gfmHeadingId(options));

marked("# heading");
// <h1 id="my-prefix-heading">heading</h1>

Get heading list

getHeadingList is a function that is exported to provide the list of headings.

The headings will each be an object with the following properties:

• text: The rendered HTML for the heading
• level: The heading level (1-7)
• raw: The raw text (stripped of HTML rendering if any; this is usefull for situation like marked("# [heading](./link)");)
• id: The id given to the heading including any prefix

import { marked } from "marked";
import { gfmHeadingId, getHeadingList } from "marked-gfm-heading-id";

marked.use(gfmHeadingId({prefix: "my-prefix-"}), {
	hooks: {
		postprocess(html) {
			const headings = getHeadingList();

			return `
<ul id="table-of-contents">
	${headings.map(({id, raw, level}) => `<li><a href="#${id}" class="h${level}">${raw}</a></li>`)}
</ul>
${html}`;
		}
	}
});

marked("# heading");
// <ul id="table-of-contents">
//   <li><a href="#my-prefix-heading" class="h1">heading</a></li>
// </ul>
// <h1 id="my-prefix-heading">heading</h1>

Clear Heading List

resetHeadings is a function to purge the stored list of headings and reset the Slugger. This is only needed when the globalSlugs option ( see below) is set to true and you wish to reset the slugger and exportable Headers list.

options

option	type	default	description
prefix	string	""	A string to prepend to all ids.
globalSlugs	bool	false	Track ids from one use of marked to the next. This ensures unique headers when parsing multiple markdown fragments and rendering the results as a single document. When set to false, the slugger and headers lists are cleared on every marked run.