feat: add get link thumbnail function

src/item/linkItem/linkItem.test.ts

@@ -0,0 +1,48 @@
+import { describe, expect, it } from 'vitest';
+
+import { ItemType } from '../itemType.js';
+import { buildLinkExtra, getLinkThumbnailUrl } from './linkItem.js';
+
+describe('getLinkThumbnailUrl', () => {
+  it('returns thumbnail over icon', () => {
+    const extra = buildLinkExtra({
+      url: 'url',
+      thumbnails: ['thumbnai'],
+      icons: ['icon'],
+    });
+    expect(getLinkThumbnailUrl(extra)).to.eq(
+      extra[ItemType.LINK].thumbnails![0],
+    );
+  });
+
+  it('return icon for empty thumbnail', () => {
+    const extra = buildLinkExtra({
+      url: 'url',
+      icons: ['icon'],
+    });
+    expect(getLinkThumbnailUrl(extra)).to.eq(extra[ItemType.LINK].icons![0]);
+    const extra1 = {
+      [ItemType.LINK]: {
+        url: 'url',
+        thumbnails: [],
+        icons: ['icon'],
+      },
+    };
+    expect(getLinkThumbnailUrl(extra1)).to.eq(extra[ItemType.LINK].icons![0]);
+  });
+
+  it('returns undefined when nothing is defined', () => {
+    const extra = buildLinkExtra({
+      url: 'string',
+      thumbnails: [],
+      icons: [],
+    });
+    expect(getLinkThumbnailUrl(extra)).to.be.undefined;
+    const extra1 = buildLinkExtra({ url: 'string', thumbnails: [] });
+    expect(getLinkThumbnailUrl(extra1)).to.be.undefined;
+    const extra2 = buildLinkExtra({ url: 'string' });
+    expect(getLinkThumbnailUrl(extra2)).to.be.undefined;
+    const extra3 = buildLinkExtra({ url: 'string', icons: [] });
+    expect(getLinkThumbnailUrl(extra3)).to.be.undefined;
+  });
+});

src/item/linkItem/linkItem.ts

@@ -47,6 +47,20 @@ export const getLinkExtra = <U extends LinkItemExtra>(
   extra: U,
 ): U[typeof ItemType.LINK] => extra[ItemType.LINK];
 
+export const getLinkThumbnailUrl = <U extends LinkItemExtra>(
+  extra: U,
+): string | undefined => {
+  const { thumbnails, icons } = getLinkExtra(extra);
+
+  if (thumbnails && thumbnails.length > 0) {
+    return thumbnails[0];
+  }
+  if (icons && icons.length > 0) {
+    return icons[0];
+  }
+  return;
+};
+
 export const buildLinkExtra = (
   extra: LinkItemExtraProperties,
 ): LinkItemExtra => ({