astro/packages/markdown/remark/src/rehype-collect-headers.ts
2022-07-16 09:47:09 +00:00

73 lines
2.1 KiB
TypeScript

import Slugger from 'github-slugger';
import { toHtml } from 'hast-util-to-html';
import { visit } from 'unist-util-visit';
import type { MarkdownHeader, RehypePlugin } from './types.js';
export default function createCollectHeaders() {
const headers: MarkdownHeader[] = [];
const slugger = new Slugger();
function rehypeCollectHeaders(): ReturnType<RehypePlugin> {
return function (tree) {
visit(tree, (node) => {
if (node.type !== 'element') return;
const { tagName } = node;
if (tagName[0] !== 'h') return;
const [_, level] = tagName.match(/h([0-6])/) ?? [];
if (!level) return;
const depth = Number.parseInt(level);
let text = '';
let isJSX = false;
visit(node, (child, __, parent) => {
if (child.type === 'element' || parent == null) {
return;
}
if (child.type === 'raw') {
if (child.value.match(/^\n?<.*>\n?$/)) {
return;
}
}
if (child.type === 'text' || child.type === 'raw') {
if (new Set(['code', 'pre']).has(parent.tagName)) {
text += child.value;
} else {
text += child.value.replace(/\{/g, '${');
isJSX = isJSX || child.value.includes('{');
}
}
});
node.properties = node.properties || {};
if (typeof node.properties.id !== 'string') {
if (isJSX) {
// HACK: serialized JSX from internal plugins, ignore these for slug
const raw = toHtml(node.children, { allowDangerousHtml: true })
.replace(/\n(<)/g, '<')
.replace(/(>)\n/g, '>');
// HACK: for ids that have JSX content, use $$slug helper to generate slug at runtime
node.properties.id = `$$slug(\`${text}\`)`;
(node as any).type = 'raw';
(
node as any
).value = `<${node.tagName} id={${node.properties.id}}>${raw}</${node.tagName}>`;
} else {
let slug = slugger.slug(text);
if (slug.endsWith('-')) slug = slug.slice(0, -1);
node.properties.id = slug;
}
}
headers.push({ depth, slug: node.properties.id, text });
});
};
}
return {
headers,
rehypeCollectHeaders,
};
}