a18hvcryt: Delete the signed-in person's own post from its menu

src/lib/feed-model.ts

@@ -12,6 +12,8 @@ export interface CardMedia {
 export interface CardPost {
   key: string;
   id: string | null;
+  /** The author's id on the feed, for matching against the signed-in feed user id. */
+  authorId: string | null;
   authorName: string;
   authorPictureUrl: string | null;
   publishedAt: string | null;
@@ -95,6 +97,8 @@ export function toCardPost(item: unknown, index = 0): CardPost | null {
   return {
     key: id ?? `${publishedAt ?? "unknown"}#${index}`,
     id,
+    authorId:
+      typeof author.id === "string" || typeof author.id === "number" ? String(author.id) : null,
     authorName: authorName(author),
     authorPictureUrl: str(author.profilePictureUrl),
     publishedAt,
@@ -151,3 +155,8 @@ export function relativeTime(publishedAt: string | null, now: number = Date.now(
   if (d < 7) return `${d}d ago`;
   return new Date(t).toLocaleDateString("en-US", { month: "short", day: "numeric", year: "numeric" });
 }
+
+/** Delete is offered only on the signed-in person's own post. */
+export function canDelete(post: CardPost, feedUserId: string | null | undefined): boolean {
+  return !!feedUserId && !!post.id && post.authorId !== null && post.authorId === feedUserId;
+}