fix: text compose papercuts (#270)

* make fixes

* cleanup

js/desktop/src/lib/immersive-text.ts

@@ -0,0 +1,7 @@
+/** Font scale for short messages shown as large centered text. Shared by the
+ *  composer and the posted view so editing matches the final render. */
+export function getImmersiveTextStyle(length: number) {
+  if (length < 30) return { size: 'text-5xl', weight: 'font-semibold' };
+  if (length < 70) return { size: 'text-3xl', weight: 'font-semibold' };
+  return { size: 'text-2xl', weight: 'font-normal' };
+}

js/desktop/src/lib/link-metadata.ts

@@ -14,3 +14,11 @@ export function extractUrls(text: string): string[] {
   // should only yield a single preview card.
   return Array.from(new Set(Array.from(text.matchAll(URL_REGEX), (m) => m[0])));
 }
+
+export function domainFromUrl(url: string): string {
+  try {
+    return new URL(url).hostname.replace(/^www\./, '');
+  } catch {
+    return url;
+  }
+}

js/desktop/src/lib/markdown.ts

@@ -0,0 +1,5 @@
+export function hasMarkdownFormatting(content: string): boolean {
+  return /^#{1,6} |^\s*[-*+] |^\s*\d+\. |^```|`[^`]+`|\*\*|__|\*\S[^*]*\*|\b_\S[^_]*_\b|^>/m.test(
+    content,
+  );
+}