react-markdown-toc

react-markdown-toc is a library designed for React applications, focused on generating a Table of Contents (TOC) from Markdown text.

Preview Link

Features

• Fast and Accurate: Optimized for runtime performance, ensuring quick and accurate identification of the currently active section in the document. This feature is particularly beneficial for interactive documents where users might scroll frequently.
• Fully Customizable: Supports a wide range of customization options, including list style and link behavior, suitable for various design needs.
• Server and Client Side Support: Compatible with React server components and client components, enabling it to adapt to different rendering strategies.

Installation

You can install react-markdown-toc using the following commands:

npm install react-markdown-toc

Usage

fromMarkdown

The fromMarkdown function is used to generate a TOC tree from a Markdown text.

Example Usage:

import { fromMarkdown } from 'react-markdown-toc'

const [result, map] = fromMarkdown(`## Heading 1\n\n### Heading 1.1\n\n## Heading 2`)

The fromMarkdown function returns a tuple containing the TOC tree and a map linking IDs to keys within the tree.

Server Component

The server component does not support custom rendering functions; it renders the ul, li, and a tags in a fixed manner.

Example Usage:

import fs from 'node:fs/promises'
import { TOC } from 'react-markdown-toc/server'

async function App() {
  const markdown = await fs.readFile('.example.md', 'utf-8')
  return <TOC markdown={markdown} className='ml-4' ul='pl-4' />
}

Props

• markdown: string, required
  • The Markdown text to generate the TOC from.
• className: string, optional
  • Adds a custom class name to the outermost <ul> for style customization.
• scrollAlign: start|center|end, optional, default: center
  • Determines which TOC item is considered active based on the scroll position, especially useful when multiple headings are visible in the viewport simultaneously.
  • The options are start (the element closest to the top of the viewport), center (the element closest to the center of the viewport), and end (the element closest to the bottom of the viewport).
• throttleTime: number, optional, default: 1000
  • Controls the throttling time for the scroll event to improve performance.

Client Component

The client component allows full customization of rendering, including the functions for rendering the list, list items, and links.

Example Usage:

Use shadcn/ui to implement a collapsible TOC list.

Preview Link

import { useRouter } from 'next/navigation'
import { TOC } from 'react-markdown-toc/client'
import { Collapsible, CollapsibleTrigger, CollapsibleContent } from '@/components/ui/collapsible'

function CustomTOC({ tocData }) {
  const router = useRouter()
  return (
    <TOC
      toc={toc}
      scrollAlign='start'
      renderList={children => (
        <CollapsibleContent className='pl-4 overflow-hidden data-[state=open]:animate-collapsible-down data-[state=closed]:animate-collapsible-up'>
          {children}
        </CollapsibleContent>
      )}
      renderListItem={(children, open) => <Collapsible open={open}>{children}</Collapsible>}
      renderLink={(children, href, active) => (
        <CollapsibleTrigger>
          <span
            data-active={active}
            role='button'
            onClick={() => {
              router.push(href, { scroll: false })
              const target = document.querySelector(href)
              target?.scrollIntoView({ behavior: 'smooth' })
            }}
          >
            {children}
          </span>
        </CollapsibleTrigger>
      )}
    />
  )
}

Props

• toc: readonly [Result, Map<string, string>], required
  • Obtained through the fromMarkdown method. This tuple contains the TOC tree and a map linking IDs to keys within the tree.
• scrollAlign: start|center|end, optional, default: center
  • Determines which TOC item is considered active based on the scroll position, especially useful when multiple headings are visible in the viewport simultaneously.
  • The options are start (the element closest to the top of the viewport), center (the element closest to the center of the viewport), and end (the element closest to the bottom of the viewport).
• throttleTime: number, optional, default: 1000
  • Controls the throttling time for the scroll event to improve performance.
• renderList: (children: React.ReactNode, active: boolean) => React.ReactNode, required
  • A custom rendering function for the list component, providing full control over the list's appearance and behavior.
• renderListItem: (children: React.ReactNode, active: boolean) => React.ReactNode, required
  • A custom rendering function for each list item, allowing for individual customization of list items within the TOC.
• renderLink: (children: React.ReactNode, url: string, active: boolean) => React.ReactNode, required
  • A custom function for rendering links, where you can specify the content, the target URL, and the active state styling or behavior.

Contribution

Contributions are always welcome!

License

MIT