Remove trailing variation selector code for legacy emojis (#37320)

app/javascript/mastodon/features/emoji/normalize.test.ts

@@ -33,6 +33,7 @@ describe('emojiToUnicodeHex', () => {
     ['⚫', '26AB'],
     ['🖤', '1F5A4'],
     ['💀', '1F480'],
+    ['❤️', '2764'], // Checks for trailing variation selector removal.
     ['💂‍♂️', '1F482-200D-2642-FE0F'],
   ] as const)(
     'emojiToUnicodeHex converts %s to %s',

app/javascript/mastodon/features/emoji/normalize.ts

@@ -30,6 +30,12 @@ export function emojiToUnicodeHex(emoji: string): string {
       codes.push(code);
     }
   }
+
+  // Handles how Emojibase removes the variation selector for single code emojis.
+  // See: https://emojibase.dev/docs/spec/#merged-variation-selectors
+  if (codes.at(1) === VARIATION_SELECTOR_CODE && codes.length === 2) {
+    codes.pop();
+  }
   return hexNumbersToString(codes);
 }