enyaxu / markdown-it-anchor

Header anchors for markdown-it.

markdown-it-anchor

Header anchors for markdown-it.

Usage

const md = require('markdown-it')()
  .use(require('markdown-it-anchor'), opts)

See a demo as JSFiddle.

The opts object can contain:

Name	Description	Default
level	Minimum level to apply anchors on or array of selected levels.	1
slugify	A custom slugification function.	See index.js
uniqueSlugStartIndex	Used for unique slug start index.	1
permalink	Whether to add permalinks next to titles.	false
renderPermalink	A custom permalink rendering function.	See index.js
permalinkClass	The class of the permalink anchor.	header-anchor
permalinkSymbol	The symbol in the permalink anchor.	¶
permalinkBefore	Place the permalink before the title.	false
permalinkHref	A custom permalink href rendering function.	See index.js
callback	Called with token and info after rendering.	undefined

The renderPermalink function takes the slug, an options object with the above options, and then all the usual markdown-it rendering arguments.

All headers above level will then have an id attribute with a slug of their content. level can also be an array of headers levels to apply the anchor, like [2, 3] to have an anchor on only level 2 and 3 headers.

If permalink is true, a ¶ symbol linking to the header itself will be added.

You may want to use the link symbol as permalinkSymbol, or a symbol from your favorite web font.

The callback option is a function that will be called at the end of rendering with the token and an info object. The info object has title and slug properties with the token content and the slug used for the identifier.

User-Friendly URLs

Starting from v5.0.0, markdown-it-anchor dropped package string keeping it's core value of being an unopinionated and secure library. Yet, users looking for backward compatibility may want the old slugify:

$ npm i -S string

const string = require('string')
const legacySlugify = s => string(s).slugify().toString()

const md = require('markdown-it')()
const anchor = require('markdown-it-anchor', {
	slugify: legacySlugify
})

Unicode Support

Unicode is supported by default. Yet, if you are looking for a "prettier" --opinionated-- link, i.e without %xx, you may want to take a look at uslug:

$ npm i -S uslug

const uslug = require('uslug')
const uslugify = s => uslug(s)

const md = require('markdown-it')()
const anchor = require('markdown-it-anchor', {
	slugify: uslugify
})

Table of Contents

Looking for an automatic table of contents (TOC) generator? Take a look at markdown-it-toc-done-right it's made from the ground to be a great companion of this plugin.