Storyden

import DOMPurify from "dompurify"; import html from "remark-html"; import remarkParse from "remark-parse"; import TurndownService from "turndown"; import { unified } from "unified"; import { deriveError } from "./error"; const SANITIZE_CONFIG = { ALLOWED_TAGS: [ "p", "br", "strong", "em", "u", "s", "del", "code", "pre", "blockquote", "h1", "h2", "h3", "h4", "h5", "h6", "ul", "ol", "li", "a", "img", "table", "thead", "tbody", "tr", "td", "th", "hr", ], ALLOWED_ATTR: ["href", "src", "alt", "title", "class", "target", "rel"], ALLOW_DATA_ATTR: false, }; const HTML_TO_MD_SANITIZE_CONFIG = { ...SANITIZE_CONFIG, ALLOWED_TAGS: [...SANITIZE_CONFIG.ALLOWED_TAGS, "b", "i", "strike"], }; const turndownService = new TurndownService({ headingStyle: "atx", codeBlockStyle: "fenced", bulletListMarker: "-", }); turndownService.addRule("strikethrough", { filter: ["del", "s"], replacement: (content) => `~~${content}~~`, }); export async function markdownToHTML(markdown: string): Promise<string> { try { const result = await unified() .use(remarkParse) .use(html, { sanitize: false }) .process(markdown); const rawHTML = String(result); DOMPurify.addHook("afterSanitizeAttributes", (node) => { if (node.tagName === "A") { const href = node.getAttribute("href"); if (href && /^https?:\/\//i.test(href)) { node.setAttribute("target", "_blank"); node.setAttribute("rel", "noopener noreferrer"); } } if (node.tagName === "IMG") { const src = node.getAttribute("src"); if (src && !/^(https?:\/\/|\/)/i.test(src)) { node.removeAttribute("src"); } } }); const sanitized = DOMPurify.sanitize(rawHTML, SANITIZE_CONFIG); DOMPurify.removeHooks("afterSanitizeAttributes"); return sanitized; } catch (error) { const preview = markdown.length > 100 ? `${markdown.slice(0, 100)}...` : markdown; console.error("Failed to process markdown to HTML:", { error, markdownPreview: preview, }); throw new Error(`Markdown processing failed: ${deriveError(error)}`); } } export function htmlToMarkdown(html: string): string { const sanitized = DOMPurify.sanitize(html, HTML_TO_MD_SANITIZE_CONFIG); return turndownService.turndown(sanitized); }