51 lines
1.3 KiB
TypeScript
51 lines
1.3 KiB
TypeScript
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import Slugger from 'github-slugger';
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import { visit } from 'unist-util-visit';
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import { jsToTreeNode } from './utils.js';
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export interface MarkdownHeading {
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depth: number;
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slug: string;
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text: string;
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}
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export default function rehypeCollectHeadings() {
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const slugger = new Slugger();
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return function (tree: any) {
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const headings: MarkdownHeading[] = [];
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visit(tree, (node) => {
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if (node.type !== 'element') return;
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const { tagName } = node;
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if (tagName[0] !== 'h') return;
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const [_, level] = tagName.match(/h([0-6])/) ?? [];
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if (!level) return;
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const depth = Number.parseInt(level);
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let text = '';
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visit(node, (child, __, parent) => {
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if (child.type === 'element' || parent == null) {
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return;
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}
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if (child.type === 'raw' && child.value.match(/^\n?<.*>\n?$/)) {
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return;
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}
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if (new Set(['text', 'raw', 'mdxTextExpression']).has(child.type)) {
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text += child.value;
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}
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});
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node.properties = node.properties || {};
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if (typeof node.properties.id !== 'string') {
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let slug = slugger.slug(text);
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if (slug.endsWith('-')) {
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slug = slug.slice(0, -1);
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}
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node.properties.id = slug;
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}
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headings.push({ depth, slug: node.properties.id, text });
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});
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tree.children.unshift(
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jsToTreeNode(`export function getHeadings() { return ${JSON.stringify(headings)} }`)
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);
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};
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}
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