skills/wix-headless-templates/blog/project/src/wix/blog/authors-core.ts

// Author rules and DTO mapping — transport-agnostic, imported by both ./authors.ts and the REST
// twin in templates/blog/rest/authors.ts. A post's author is a site member: `post.memberId` →
// the Members API's PUBLIC fieldset (nickname + photo), looked up in ONE batched query per page.
// Authors are decoration on a card: every failure degrades to "no byline", never to a placeholder
// name. Imports are type-only so a strip to JS emits no imports.
import type { BlogAuthor } from "./types";
import type { ImgSrc, Raw } from "./posts-core";

/** The PUBLIC fieldset covers everything a byline needs: `profile.nickname` and `profile.photo`. */
export const AUTHOR_FIELDSETS = ["PUBLIC"] as const;

/** Avatar size every byline gets — one scaled square URL per author. */
export const AVATAR_SIZE = 96;

/** Distinct, non-empty ids in first-seen order — one query per page, never one per card. */
export function uniqueIds(ids: readonly (string | null | undefined)[]): string[] {
  return [...new Set(ids.filter((id): id is string => Boolean(id)))];
}

/**
 * The members query as the REST body — the SDK spells it queryMembers({ fieldsets }).in("_id", ids)
 * .limit(n). Members page by OFFSET (`paging`), unlike posts.
 */
export function authorsQuery(ids: string[]): Raw {
  return { fieldsets: AUTHOR_FIELDSETS, query: { filter: { id: { $in: ids } }, paging: { limit: ids.length } } };
}

/**
 * A member photo in the form imgSrc scales. A Wix-hosted photo carries a media id (`_id` on the
 * SDK, `id` on REST) → the wix:image form; an avatar imported from a social login is an external
 * URL with an EMPTY id → passed through as-is (imgSrc leaves non-Wix URLs alone).
 */
export function photoValue(photo: Raw | undefined | null): string {
  if (!photo) return "";
  const id = photo._id ?? photo.id;
  if (id) return `wix:image://v1/${id}/${id}${photo.width && photo.height ? `#originWidth=${photo.width}&originHeight=${photo.height}` : ""}`;
  return photo.url ?? "";
}

export function toAuthor(raw: Raw, imgSrc: ImgSrc): BlogAuthor {
  return {
    id: raw._id ?? raw.id ?? "",
    name: raw.profile?.nickname ?? "",
    avatarUrl: imgSrc(photoValue(raw.profile?.photo), AVATAR_SIZE, AVATAR_SIZE),
  };
}

/** Authors keyed by id — a plain object, not a Map, so it survives serialization into island props. */
export function indexAuthors(authors: BlogAuthor[]): Record<string, BlogAuthor> {
  return Object.fromEntries(authors.filter((a) => a.id).map((a) => [a.id, a]));
}