server/utils/formatting.ts

import { sanitizeHtml } from "@sanitization";
import linkifyHtml from "linkify-html";
import linkifyStr from "linkify-string";
import { parse } from "marked";

/**
 * Converts plaintext, MFM or Markdown to HTML
 * @param text Text to convert
 * @param content_type Content type of the text (optional, defaults to plaintext)
 * @returns HTML
 */
export const convertTextToHtml = async (
	text: string,
	content_type?: string
) => {
	if (content_type === "text/markdown") {
		return linkifyHtml(await sanitizeHtml(parse(text)));
	} else if (content_type === "text/x.misskeymarkdown") {
		// Parse as MFM
		// TODO: Implement MFM
		return text;
	} else {
		// Parse as plaintext
		return linkifyStr(text)
			.split("\n")
			.map(line => `<p>${line}</p>`)
			.join("\n");
	}
};