roadmap/quartz/plugins/transformers/toc.ts

64 lines
1.6 KiB
TypeScript

import { QuartzTransformerPlugin } from "../types"
import { Root } from "mdast"
import { visit } from "unist-util-visit"
import { toString } from "mdast-util-to-string"
import { slug as slugAnchor } from 'github-slugger'
export interface Options {
maxDepth: 1 | 2 | 3 | 4 | 5 | 6,
minEntries: 1,
showByDefault: boolean
}
const defaultOptions: Options = {
maxDepth: 3,
minEntries: 1,
showByDefault: true,
}
interface TocEntry {
depth: number,
text: string,
slug: string
}
export const TableOfContents: QuartzTransformerPlugin<Partial<Options> | undefined> = (userOpts) => {
const opts = { ...defaultOptions, ...userOpts }
return {
name: "TableOfContents",
markdownPlugins() {
return [() => {
return async (tree: Root, file) => {
const display = file.data.frontmatter?.enableToc ?? opts.showByDefault
if (display) {
const toc: TocEntry[] = []
let highestDepth: number = opts.maxDepth
visit(tree, 'heading', (node) => {
if (node.depth <= opts.maxDepth) {
const text = toString(node)
highestDepth = Math.min(highestDepth, node.depth)
toc.push({
depth: node.depth,
text,
slug: slugAnchor(text)
})
}
})
if (toc.length > opts.minEntries) {
file.data.toc = toc.map(entry => ({ ...entry, depth: entry.depth - highestDepth }))
}
}
}
}]
},
}
}
declare module 'vfile' {
interface DataMap {
toc: TocEntry[]
}
}