feat: add markdown renderer

src/lib/github/webhooks/handlers/release-created.ts

@@ -1,6 +1,7 @@
 import type { HandlerFunction } from "@octokit/webhooks/types";
 
 import { bot } from "#bot";
+import { renderMarkdown } from "#telegram";
 
 import { escapeHtml } from "../../../escape-html.ts";
 import { botText, getRepoHashtag } from "./_utils.ts";
@@ -11,14 +12,14 @@ export const releaseCreatedCallback: HandlerFunction<"release.created", unknown>
   const repoHashtag = getRepoHashtag(repo.name);
 
   if (release.body) {
-    const releaseNotesPreview = release.body.length > 2000 ? `${release.body.slice(0, 2000)}\n...` : release.body;
+    const notes = renderMarkdown(release.body);
 
     await bot.announce(
       botText("e_release_created_with_notes", {
         repoName: escapeHtml(repo.name),
         releaseTag: escapeHtml(release.tag_name),
         releaseUrl: escapeHtml(release.html_url),
-        notes: releaseNotesPreview,
+        notes,
         repoHashtag,
       }),
       { link_preview_options: { prefer_small_media: true, url: release.html_url } },

src/lib/telegram/index.ts

@@ -1,3 +1,4 @@
 export * from "./CommandParser.ts";
 export * from "./createCommand.ts";
+export * from "./render-markdown.ts";
 export * as zs from "./schemas.ts";

src/lib/telegram/render-markdown.spec.ts

@@ -0,0 +1,112 @@
+import assert from "node:assert";
+import { it } from "node:test";
+
+import { renderMarkdown } from "./render-markdown.ts";
+
+it("should render raw text", () => {
+  const markdown = "This is a simple text without any markdown.";
+
+  assert.equal(renderMarkdown(markdown), markdown);
+});
+
+it("should trim leading and trailing whitespace", () => {
+  const markdown = "\n\n   \n\nThis is a text with leading and trailing spaces.\n   \n  ";
+  const expected = "This is a text with leading and trailing spaces.";
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should render bold text", () => {
+  const markdown = "This is **bold** text.";
+  const expected = "This is <b>bold</b> text.";
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should render links", () => {
+  const markdown = "This is a [link](https://example.com).";
+  const expected = 'This is a <a href="https://example.com">link</a>.';
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should render headings", () => {
+  const markdown = "# Heading 1\n## Heading 2\n### Heading 3";
+  const expected = "<b>Heading 1</b>\n<b>Heading 2</b>\n<b>Heading 3</b>";
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should render bullet points", () => {
+  const markdown = "- Item 1\n- Item 2\n- Item 3";
+  const expected = "• Item 1\n• Item 2\n• Item 3";
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should merge multiple empty lines", () => {
+  const markdown = "Line 1\n\n\n\nLine 2";
+  const expected = "Line 1\n\nLine 2";
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should render markdown to HTML", () => {
+  const markdown = `
+# [13.12.0](https://github.com/fullstacksjs/eslint-config/compare/v13.11.2...v13.12.0) (2025-12-16)
+
+
+### Bug Fixes
+
+* **stylistic:** fix error in rule lines-between-class-members, add new rule ([411160c](https://github.com/fullstacksjs/eslint-config/commit/411160c7f900e6417f32c671d00e8e949ca3e445))
+* **stylistic:** fix padding-line-between-statements to be more general ([956e745](https://github.com/fullstacksjs/eslint-config/commit/956e745027bfc6025554e138d2b9084e3749178b))
+* **stylistic:** fix rule name padding-line-between-statements ([d509bec](https://github.com/fullstacksjs/eslint-config/commit/d509bec4c915c6df6a486f54b2a4c486fa40702c))
+
+
+### Features
+
+* **stylistic:** add new rules ([2283711](https://github.com/fullstacksjs/eslint-config/commit/228371129db44b128ef5e733b9f477983f4f4509))
+* **stylistic:** fix padding-line-between-statements and add new rule lines-between-class-members ([5c573f8](https://github.com/fullstacksjs/eslint-config/commit/5c573f89d522b9aeb4a11e654ccb224f93076094))
+`;
+
+  const expected = `
+<b><a href="https://github.com/fullstacksjs/eslint-config/compare/v13.11.2...v13.12.0">13.12.0</a> (2025-12-16)</b>
+
+<b>Bug Fixes</b>
+
+• <b>stylistic:</b> fix error in rule lines-between-class-members, add new rule (<a href="https://github.com/fullstacksjs/eslint-config/commit/411160c7f900e6417f32c671d00e8e949ca3e445">411160c</a>)
+• <b>stylistic:</b> fix padding-line-between-statements to be more general (<a href="https://github.com/fullstacksjs/eslint-config/commit/956e745027bfc6025554e138d2b9084e3749178b">956e745</a>)
+• <b>stylistic:</b> fix rule name padding-line-between-statements (<a href="https://github.com/fullstacksjs/eslint-config/commit/d509bec4c915c6df6a486f54b2a4c486fa40702c">d509bec</a>)
+
+<b>Features</b>
+
+• <b>stylistic:</b> add new rules (<a href="https://github.com/fullstacksjs/eslint-config/commit/228371129db44b128ef5e733b9f477983f4f4509">2283711</a>)
+• <b>stylistic:</b> fix padding-line-between-statements and add new rule lines-between-class-members (<a href="https://github.com/fullstacksjs/eslint-config/commit/5c573f89d522b9aeb4a11e654ccb224f93076094">5c573f8</a>)
+`.trim();
+
+  assert.equal(renderMarkdown(markdown), expected);
+});
+
+it("should truncate output exceeding max characters", () => {
+  const longText = "1\n3\n5\n6\n8\n";
+  const rendered = renderMarkdown(longText, 5);
+  const expected = "1\n3\n5\n...";
+
+  assert.equal(rendered, expected);
+});
+
+it("should keep the line when truncating output exceeding max characters", () => {
+  const longText = "First line\nSecond line\nThird line\nFourth line\nFifth line\n";
+  const rendered = renderMarkdown(longText, 15);
+  const expected = "First line\nSecond line\n...";
+
+  assert.equal(rendered, expected);
+});
+
+it("should not add extra newline when truncating at the end of a line", () => {
+  const longText = ["Line one", "Line two", "Line three"].join("\n");
+  const rendered = renderMarkdown(longText, longText.indexOf("Line two") + 1);
+  const expected = "Line one\nLine two\n...";
+
+  assert.equal(rendered, expected);
+});

src/lib/telegram/render-markdown.ts

@@ -0,0 +1,52 @@
+import { crlfToLf, isNullOrEmptyString } from "@fullstacksjs/toolbox";
+
+const boldPattern = /\*\*(.+?)\*\*/g;
+const linkPattern = /\[([^\]]+)\]\(([^)]+)\)/g;
+
+function renderInline(content: string): string {
+  return content.replace(boldPattern, "<b>$1</b>").replace(linkPattern, '<a href="$2">$1</a>');
+}
+
+export function renderMarkdown(markdown: string, maxChars: number = Infinity): string {
+  const lines = crlfToLf(markdown)
+    .split("\n")
+    .map((l) => l.trim());
+
+  const rendered: string[] = [];
+  let lastWasEmpty = true;
+
+  for (const line of lines) {
+    if (isNullOrEmptyString(line)) {
+      if (!lastWasEmpty) rendered.push("");
+      lastWasEmpty = true;
+      continue;
+    } else {
+      lastWasEmpty = false;
+    }
+
+    const headingMatch = line.match(/^#{1,6}\s+(\S.*)$/);
+    if (headingMatch) {
+      const content = headingMatch[1];
+      rendered.push(`<b>${renderInline(content.trim())}</b>`);
+      continue;
+    }
+
+    const listMatch = line.match(/^\s*[*-]\s+(\S.*)$/);
+    if (listMatch) {
+      rendered.push(`• ${renderInline(listMatch[1].trim())}`);
+      continue;
+    }
+
+    rendered.push(renderInline(line));
+  }
+
+  let html = "";
+  for (const line of rendered) {
+    if (html.length > maxChars) {
+      return `${html}...`;
+    }
+    html += `${line}\n`;
+  }
+
+  return html.trim();
+}