v3: the backend is documented for deno doc, one way in every file, and the docs build and publish themselves — comments were in three shapes: file headers as // lines, as an untagged /** */ (which deno doc drops, only an @module block counts) or missing; 43 exports described by a // deno doc can't see, two JSDoc blocks sitting on the wrong declaration and one duplicated; endpoints commented in 5 of 18 route files, three ways, on router.get() calls no doc tool reads. The rule, applied to every non-test module of api/, migrations included: each opens with a /** … @module */ block; every export has JSDoc, and so does every field of an exported interface; a comment describing a declaration is /** */, // only notes code; functions open with a verb, everything else with a noun phrase; parameters are named in the prose, {@link} only for symbols in scope; whatever throws to its caller says so with @throws (for an APIException, the statuses and when); a router's JSDoc lists its endpoints, method and path, who may call it, what it does. deno doc --lint goes from 528 errors to none in api/ (shared/ keeps its 385; it is next). The lint also wanted explicit types on config.ts's settings and a few return types, JsonLdResult exported, and the routers typed Router. deno task doc builds the HTML reference into docs/ from every module of api/ and shared/ but the tests, deno task doc:lint lints it; the index page is the module doc of a root mod.ts (deno.json's exports), which introduces the backend, shared/ and the frontend to come and links every module, and mod.test.ts fails when one is missing. The docs workflow builds it on every push to main that touches them and publishes it to the gh-pages branch, like publish-assistant's. Two defects found along the way are fixed: a private playlist's cover was served to anyone who had its id or slug, and now needs its owner's media token, as private dump files do (playlistImageUrl adds it for private playlists only, so public cover URLs stay the same for everyone); og.ts and static.ts each filled index.html's placeholders, and now share lib/index-html.ts, so the OG middleware picks up a rebuilt index.html instead of keeping the first it read. The README states the documentation rule. 205 backend and 628 frontend tests pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/services/follow-service.ts

@@ -1,3 +1,9 @@
+/**
+ * Following users and playlists, and the feeds made of what one follows.
+ *
+ * @module
+ */
+
 import { APIErrorCode } from "../../shared/api.ts";
 import { APIException } from "../lib/api-exception.ts";
 import type { Dump } from "../../shared/dump.ts";
@@ -21,6 +27,12 @@ import { attachCategoryIds } from "./category-service.ts";
 
 // ── Follow / unfollow a user ──────────────────────────────────────────────────
 
+/**
+ * Makes `followerId` follow `followedUserId`, and notifies them the first
+ * time. Following again changes nothing.
+ *
+ * @throws {APIException} 400 when a user tries to follow themselves.
+ */
 export function followUser(followerId: string, followedUserId: string): void {
   if (followerId === followedUserId) {
     throw new APIException(
@@ -51,6 +63,7 @@ export function followUser(followerId: string, followedUserId: string): void {
   if (isNew) notifyUserNewFollower(followerId, followedUserId);
 }
 
+/** Makes `followerId` stop following `followedUserId`, if they did. */
 export function unfollowUser(followerId: string, followedUserId: string): void {
   db.prepare(
     `DELETE FROM follows WHERE follower_id = ? AND followed_user_id = ?;`,
@@ -59,6 +72,13 @@ export function unfollowUser(followerId: string, followedUserId: string): void {
 
 // ── Follow / unfollow a playlist ─────────────────────────────────────────────
 
+/**
+ * Makes `followerId` follow a public playlist, and notifies its owner the
+ * first time. Following again changes nothing.
+ *
+ * @throws {APIException} 404 when there is no such playlist, 403 when it is
+ * private.
+ */
 export function followPlaylist(followerId: string, playlistId: string): void {
   const row = db.prepare(
     `SELECT id, is_public FROM playlists WHERE id = ?;`,
@@ -97,6 +117,7 @@ export function followPlaylist(followerId: string, playlistId: string): void {
   if (isNew) notifyPlaylistOwnerNewFollower(followerId, playlistId);
 }
 
+/** Makes `followerId` stop following a playlist, if they did. */
 export function unfollowPlaylist(followerId: string, playlistId: string): void {
   db.prepare(
     `DELETE FROM follows WHERE follower_id = ? AND followed_playlist_id = ?;`,
@@ -105,6 +126,7 @@ export function unfollowPlaylist(followerId: string, playlistId: string): void {
 
 // ── Follow status ─────────────────────────────────────────────────────────────
 
+/** Returns the ids of every user and playlist `followerId` follows. */
 export function getFollowStatus(followerId: string): FollowStatus {
   const rawUserRows = db.prepare(
     `SELECT id, follower_id, followed_user_id, followed_playlist_id, created_at
@@ -132,6 +154,10 @@ export function getFollowStatus(followerId: string): FollowStatus {
 
 // ── Followed-users feed ───────────────────────────────────────────────────────
 
+/**
+ * Returns a page of the public dumps posted by the users `followerId` follows,
+ * newest first, optionally only those in `categoryId`.
+ */
 export function getFollowedUsersDumpFeed(
   followerId: string,
   page: number,
@@ -172,6 +198,10 @@ export function getFollowedUsersDumpFeed(
 
 // ── Followed-playlists dump feed ──────────────────────────────────────────────
 
+/**
+ * Returns a page of the public dumps in the public playlists `followerId`
+ * follows, most recently added first, optionally only those in `categoryId`.
+ */
 export function getFollowedPlaylistsDumpFeed(
   followerId: string,
   page: number,
@@ -214,6 +244,10 @@ export function getFollowedPlaylistsDumpFeed(
 
 // ── Followed playlists (as playlist objects) ──────────────────────────────────
 
+/**
+ * Returns a page of the public playlists `userId` follows, most recently
+ * followed first.
+ */
 export function getFollowedPlaylistsByUser(
   userId: string,
   page: number,
@@ -245,6 +279,7 @@ export function getFollowedPlaylistsByUser(
 
 // ── Followed users (as user objects) ─────────────────────────────────────────
 
+/** Returns a page of the users `userId` follows, most recently followed first. */
 export function getFollowedUsersByUser(
   userId: string,
   page: number,