feat: display custom emoji (NIP-30)

src/components/event/textNote/TextNoteContentDisplay.tsx

@@ -40,6 +40,19 @@ const TextNoteContentDisplay = (props: TextNoteContentDisplayProps) => {
         if (item.type === 'PlainText') {
           return <PlainTextDisplay plainText={item} />;
         }
+        if (item.type === 'URL') {
+          if (isImageUrl(item.content)) {
+            return (
+              <ImageDisplay
+                url={item.content}
+                initialHidden={
+                  !config().showImage || event().contentWarning().contentWarning || !props.embedding
+                }
+              />
+            );
+          }
+          return <SafeLink class="text-blue-500 underline" href={item.content} />;
+        }
         if (item.type === 'TagReference') {
           const resolved = resolveTagReference(item, props.event);
           if (resolved == null) return null;
@@ -88,18 +101,16 @@ const TextNoteContentDisplay = (props: TextNoteContentDisplayProps) => {
             </button>
           );
         }
-        if (item.type === 'URL') {
-          if (isImageUrl(item.content)) {
-            return (
-              <ImageDisplay
-                url={item.content}
-                initialHidden={
-                  !config().showImage || event().contentWarning().contentWarning || !props.embedding
-                }
-              />
-            );
-          }
-          return <SafeLink class="text-blue-500 underline" href={item.content} />;
+        if (item.type === 'CustomEmoji') {
+          const emojiUrl = event().getEmojiUrl(item.shortcode);
+          if (emojiUrl == null) return item.content;
+          return (
+            <img
+              class="inline-block h-6 max-w-[64px] align-middle"
+              src={emojiUrl}
+              alt={item.shortcode}
+            />
+          );
         }
         console.error('Not all ParsedTextNoteNodes are covered', item);
         return null;

src/nostr/event.ts

@@ -2,6 +2,8 @@ import uniq from 'lodash/uniq';
 import { Kind, Event as NostrEvent } from 'nostr-tools';
 import { z } from 'zod';
 
+import { isImageUrl } from '@/utils/imageUrl';
+
 export type EventMarker = 'reply' | 'root' | 'mention';
 
 // NIP-10
@@ -42,6 +44,24 @@ const eventSchema = z.object({
 });
 */
 
+const EmojiTagSchema = z.tuple([
+  z.literal('emoji'),
+  z.string().regex(/^[a-zA-Z0-9]+$/, { message: 'shortcode should be alpahnumeric' }),
+  z.string().url().refine(isImageUrl),
+]);
+
+export type EmojiTag = z.infer<typeof EmojiTagSchema>;
+
+const ensureSchema =
+  <T>(schema: z.Schema<T>) =>
+  (value: any): value is T => {
+    const result = schema.safeParse(value);
+    if (!result.success) {
+      console.warn('failed to parse value', value, schema);
+    }
+    return result.success;
+  };
+
 const eventWrapper = (event: NostrEvent) => {
   let memoizedMarkedEventTags: MarkedEventTag[] | undefined;
 
@@ -73,6 +93,9 @@ const eventWrapper = (event: NostrEvent) => {
     eTags(): string[][] {
       return event.tags.filter(([tagName, eventId]) => tagName === 'e' && isValidId(eventId));
     },
+    emojiTags(): EmojiTag[] {
+      return event.tags.filter(ensureSchema(EmojiTagSchema));
+    },
     taggedEventIds(): string[] {
       return this.eTags().map(([, eventId]) => eventId);
     },
@@ -152,6 +175,12 @@ const eventWrapper = (event: NostrEvent) => {
       if (index < 0 || index >= event.tags.length) return false;
       return event.content.includes(`#[${index}]`);
     },
+    getEmojiUrl(shortcode: string): string | null {
+      const emojiTag = this.emojiTags().find(([, code]) => code === shortcode);
+      if (emojiTag == null) return null;
+      const [, , url] = emojiTag;
+      return url;
+    },
   };
 };
 

src/nostr/parseTextNote.test.ts

@@ -186,6 +186,40 @@ describe('parseTextNote', () => {
     const expected: ParsedTextNoteNode[] = [{ type: 'PlainText', content }];
     assert.deepStrictEqual(parsed, expected);
   });
+
+  it.each([
+    {
+      given: ':bunhd:',
+      expected: [{ type: 'CustomEmoji', content: ':bunhd:', shortcode: 'bunhd' }],
+    },
+    {
+      given: 'Good morning! :pv:!',
+      expected: [
+        { type: 'PlainText', content: 'Good morning! ' },
+        { type: 'CustomEmoji', content: ':pv:', shortcode: 'pv' },
+        { type: 'PlainText', content: '!' },
+      ],
+    },
+    {
+      given: ':hello:world:',
+      expected: [
+        { type: 'CustomEmoji', content: ':hello:', shortcode: 'hello' },
+        { type: 'PlainText', content: 'world:' },
+      ],
+    },
+  ])('should parse text note which includes custom emoji ($emoji)', ({ given, expected }) => {
+    const parsed = parseTextNote(given);
+    assert.deepStrictEqual(parsed, expected);
+  });
+
+  it.each([':bunhd_hop:', ':hello', '::: NOSTR :::'])(
+    'should parse text note which includes invalid custom emoji ($emoji)',
+    (content) => {
+      const parsed = parseTextNote(content);
+      const expected: ParsedTextNoteNode[] = [{ type: 'PlainText', content }];
+      assert.deepStrictEqual(parsed, expected);
+    },
+  );
 });
 
 describe('resolveTagReference', () => {

src/nostr/parseTextNote.ts

@@ -12,10 +12,15 @@ export type PlainText = {
   content: string;
 };
 
+export type UrlText = {
+  type: 'URL';
+  content: string;
+};
+
 export type TagReference = {
   type: 'TagReference';
-  tagIndex: number;
   content: string;
+  tagIndex: number;
 };
 
 export type Bech32Entity = {
@@ -34,12 +39,20 @@ export type HashTag = {
   tagName: string;
 };
 
-export type UrlText = {
-  type: 'URL';
+// NIP-30
+export type CustomEmoji = {
+  type: 'CustomEmoji';
   content: string;
+  shortcode: string;
 };
 
-export type ParsedTextNoteNode = PlainText | TagReference | Bech32Entity | HashTag | UrlText;
+export type ParsedTextNoteNode =
+  | PlainText
+  | UrlText
+  | TagReference
+  | Bech32Entity
+  | HashTag
+  | CustomEmoji;
 
 export type ParsedTextNote = ParsedTextNoteNode[];
 
@@ -58,21 +71,23 @@ export type MentionedUser = {
   pubkey: string;
 };
 
+const urlRegex =
+  /(?<url>(?:https?|wss?):\/\/[-a-zA-Z0-9.]+(:\d{1,5})?(?:\/[-[\]~!$&'()*+.,:;@&=%\w]+|\/)*(?:\?[-[\]~!$&'()*+.,/:;%@&=\w?]+)?(?:#[-[\]~!$&'()*+.,/:;%@\w&=?#]+)?)/g;
 const tagRefRegex = /(?:#\[(?<idx>\d+)\])/g;
-const hashTagRegex = /#(?<hashtag>[\p{Letter}\p{Number}_]+)/gu;
 // raw NIP-19 codes, NIP-21 links (NIP-27)
 // nrelay and naddr is not supported by nostr-tools
 const mentionRegex =
   /(?<mention>(?<nip19>nostr:)?(?<bech32>(?:npub|note|nprofile|nevent)1[ac-hj-np-z02-9]+))/gi;
-const urlRegex =
-  /(?<url>(?:https?|wss?):\/\/[-a-zA-Z0-9.]+(:\d{1,5})?(?:\/[-[\]~!$&'()*+.,:;@&=%\w]+|\/)*(?:\?[-[\]~!$&'()*+.,/:;%@&=\w?]+)?(?:#[-[\]~!$&'()*+.,/:;%@\w&=?#]+)?)/g;
+const hashTagRegex = /#(?<hashtag>[\p{Letter}\p{Number}_]+)/gu;
+const customEmojiRegex = /:(?<emoji>[a-zA-Z0-9]+):/gu;
 
 const parseTextNote = (textNoteContent: string) => {
   const matches = [
-    ...textNoteContent.matchAll(tagRefRegex),
-    ...textNoteContent.matchAll(hashTagRegex),
-    ...textNoteContent.matchAll(mentionRegex),
     ...textNoteContent.matchAll(urlRegex),
+    ...textNoteContent.matchAll(tagRefRegex),
+    ...textNoteContent.matchAll(mentionRegex),
+    ...textNoteContent.matchAll(hashTagRegex),
+    ...textNoteContent.matchAll(customEmojiRegex),
   ].sort((a, b) => (a.index as number) - (b.index as number));
   let pos = 0;
   const result: ParsedTextNote = [];
@@ -137,6 +152,15 @@ const parseTextNote = (textNoteContent: string) => {
         tagName,
       };
       result.push(hashtag);
+    } else if (match.groups?.emoji) {
+      pushPlainText(index);
+      const shortcode = match.groups?.emoji;
+      const customEmoji: CustomEmoji = {
+        type: 'CustomEmoji',
+        content: match[0],
+        shortcode,
+      };
+      result.push(customEmoji);
     }
     pos = index + match[0].length;
   });

src/utils/imageUrl.ts

@@ -1,7 +1,7 @@
 export const isImageUrl = (urlString: string): boolean => {
   try {
     const url = new URL(urlString);
-    return /\.(jpeg|jpg|png|gif|webp)$/i.test(url.pathname);
+    return /\.(jpeg|jpg|png|gif|webp|apng)$/i.test(url.pathname);
   } catch {
     return false;
   }