v3: comments say what the code can't — the documentation pass wanted JSDoc on every export and every field of an exported interface, which filled the code with restatements ("The dump.", "Whether it is loading.", "The props of X.", "Renders the X.") and module docs that told a reader nothing ("The hot and new feeds, and the props every main feed of the index takes."); some were wrong as well as vague. Every comment in api/, shared/ and src/ is rewritten under one rule, now stated in the README's "Comments" section: every module and export still has a JSDoc, and it gives context (who uses it and where), usage (what a caller must know: a precondition, what it leaves to the caller, a side effect) or its place in the chain (where its input comes from, where its output goes); a field, parameter, private function or local gets one only when it adds to its parent's, and context about a whole type goes on the type; a type's doc is phrased from the value's side ("Returned to Y by X when Z", "Passed to Y by X"); full sentences, as short as they can be, no label-colon-list; // goes wherever the code isn't obvious and says why, and the section banners and narration go. Every claim was checked against the code, which turned up some forty comments that were wrong: DumpCard's claimed it was only used by the hot and new feeds, the WebSocket welcome claimed to be a socket's first message (presence comes first), UpdateUserRequest said null removes a description (it keeps it), deletedDumpIds leaves out that it also holds dumps made private, THEME_COLOR claimed to mirror index.html's, and the like. The routers' JSDoc now says where they are mounted and what becomes of a thrown APIException. doc-lint.ts lets a field without a doc through; a module or export without one still fails. No code changes; 204 backend and 628 frontend tests pass, and doc:lint, deno check, deno lint and tsc are clean.

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

api/validators/category.ts

@@ -1,5 +1,6 @@
 /**
- * Guards for the category request bodies.
+ * Checks the shape of the category request bodies, for the category routes to
+ * answer a 400. The category service checks the slug and name themselves.
  *
  * @module
  */
@@ -9,7 +10,7 @@ import type {
   UpdateCategoryRequest,
 } from "../../shared/category.ts";
 
-/** Checks whether `obj` is a valid {@link CreateCategoryRequest}. */
+/** Checks whether `obj` has the fields of a {@link CreateCategoryRequest}. */
 export function isCreateCategoryRequest(
   obj: unknown,
 ): obj is CreateCategoryRequest {
@@ -21,7 +22,7 @@ export function isCreateCategoryRequest(
   return true;
 }
 
-/** Checks whether `obj` is a valid {@link UpdateCategoryRequest}. */
+/** Checks whether `obj` has the fields of an {@link UpdateCategoryRequest}. */
 export function isUpdateCategoryRequest(
   obj: unknown,
 ): obj is UpdateCategoryRequest {

api/validators/comment.ts

@@ -1,5 +1,5 @@
 /**
- * Guards for the comment request bodies.
+ * Checks the comment request bodies, for the comment routes to answer a 400.
  *
  * @module
  */
@@ -11,8 +11,9 @@ import type {
 import { VALIDATION } from "../../shared/validation.ts";
 
 /**
- * Checks whether `obj` is a valid {@link CreateCommentRequest}: a body that
- * isn't blank and fits `VALIDATION.COMMENT_BODY_MAX`.
+ * Checks whether `obj` is a {@link CreateCommentRequest} whose body isn't
+ * blank and fits `VALIDATION.COMMENT_BODY_MAX`. A null `parentId` passes, as a
+ * top-level comment.
  */
 export function isCreateCommentRequest(
   obj: unknown,
@@ -27,8 +28,8 @@ export function isCreateCommentRequest(
 }
 
 /**
- * Checks whether `obj` is a valid {@link UpdateCommentRequest}: a body that
- * isn't blank and fits `VALIDATION.COMMENT_BODY_MAX`.
+ * Checks whether `obj` is an {@link UpdateCommentRequest} whose body isn't
+ * blank and fits `VALIDATION.COMMENT_BODY_MAX`.
  */
 export function isUpdateCommentRequest(
   obj: unknown,

api/validators/dump.ts

@@ -1,6 +1,7 @@
 /**
- * Guards for the dump request bodies. File dumps arrive as multipart forms
- * and are checked in their route.
+ * Checks the JSON bodies that `routes/dumps.ts` takes to post a link and to
+ * edit a dump. A file dump arrives as a multipart form instead, and
+ * `dump-service.ts` checks its title and comment.
  *
  * @module
  */
@@ -16,8 +17,9 @@ function isStringArray(value: unknown): value is string[] {
 }
 
 /**
- * Checks whether `obj` is a valid {@link CreateUrlDumpRequest}, its title and
- * comment within the `VALIDATION` limits.
+ * Checks whether `obj` is a {@link CreateUrlDumpRequest} whose title and
+ * comment fit the `VALIDATION` limits. It leaves the URL to `createUrlDump`,
+ * which rejects anything but a public http(s) URL.
  */
 export function isCreateUrlDumpRequest(
   obj: unknown,
@@ -47,9 +49,9 @@ export function isCreateUrlDumpRequest(
 }
 
 /**
- * Checks whether `obj` is a valid {@link UpdateDumpRequest}: a title, when
- * given, that isn't blank, and title and comment within the `VALIDATION`
- * limits.
+ * Checks whether `obj` is an {@link UpdateDumpRequest} whose title and comment
+ * fit the `VALIDATION` limits. Unlike on creation, a title that is given must
+ * not be blank.
  */
 export function isUpdateDumpRequest(obj: unknown): obj is UpdateDumpRequest {
   if (!obj || typeof obj !== "object") return false;

api/validators/playlist.ts

@@ -1,5 +1,5 @@
 /**
- * Guards for the playlist request bodies.
+ * Checks the playlist request bodies, for the playlist routes to answer a 400.
  *
  * @module
  */
@@ -12,8 +12,9 @@ import type {
 import { VALIDATION } from "../../shared/validation.ts";
 
 /**
- * Checks whether `obj` is a valid {@link CreatePlaylistRequest}: a non-empty
- * title, and title and description within the `VALIDATION` limits.
+ * Checks whether `obj` is a {@link CreatePlaylistRequest} with a title, and a
+ * title and description within the `VALIDATION` limits. A null description
+ * passes. A title of spaces passes too.
  */
 export function isCreatePlaylistRequest(
   obj: unknown,
@@ -40,8 +41,8 @@ export function isCreatePlaylistRequest(
 }
 
 /**
- * Checks whether `obj` is a valid {@link UpdatePlaylistRequest}: a title, when
- * given, that isn't empty, and title and description within the `VALIDATION`
+ * Checks whether `obj` is an {@link UpdatePlaylistRequest} whose title, if
+ * given, isn't empty, with a title and description within the `VALIDATION`
  * limits.
  */
 export function isUpdatePlaylistRequest(
@@ -68,7 +69,10 @@ export function isUpdatePlaylistRequest(
   return true;
 }
 
-/** Checks whether `obj` is a valid {@link ReorderPlaylistRequest}. */
+/**
+ * Checks whether `obj` is a {@link ReorderPlaylistRequest}. Whether its ids
+ * match the playlist is `reorderPlaylist`'s to check.
+ */
 export function isReorderPlaylistRequest(
   obj: unknown,
 ): obj is ReorderPlaylistRequest {

api/validators/user.ts

@@ -1,5 +1,5 @@
 /**
- * Guards for the user and authentication request bodies.
+ * Checks the JSON bodies that `routes/users.ts` receives before it reads them.
  *
  * @module
  */
@@ -12,14 +12,20 @@ import {
 } from "../../shared/user.ts";
 import { VALIDATION } from "../../shared/validation.ts";
 
-/** Checks whether `obj` is a valid {@link LoginUserRequest}. */
+/**
+ * Checks whether `obj` is a {@link LoginUserRequest}. It checks the types
+ * only: a wrong name or password is the login route's answer to give.
+ */
 export function isLoginUserRequest(obj: unknown): obj is LoginUserRequest {
   return !!obj && typeof obj === "object" &&
     "username" in obj && typeof obj.username === "string" &&
     "password" in obj && typeof obj.password === "string";
 }
 
-/** Returns `obj[key]` when `obj` is an object that has it, else undefined. */
+/**
+ * Returns `obj[key]` when `obj` is an object that has it, else undefined. The
+ * users routes whose body has no guard of its own read their fields with it.
+ */
 export function fieldOf(obj: unknown, key: string): unknown {
   return obj !== null && typeof obj === "object" && key in obj
     ? (obj as Record<string, unknown>)[key]
@@ -27,8 +33,8 @@ export function fieldOf(obj: unknown, key: string): unknown {
 }
 
 /**
- * Checks whether `obj` is a valid {@link RegisterUserRequest} (see
- * {@link validateRegisterUserRequest}).
+ * Checks whether `obj` is a valid {@link RegisterUserRequest}. When it isn't,
+ * {@link validateRegisterUserRequest} says why.
  */
 export function isRegisterUserRequest(
   obj: unknown,
@@ -37,9 +43,10 @@ export function isRegisterUserRequest(
 }
 
 /**
- * Checks a registration body — its shape, the email's form, and the username
- * and password against the `VALIDATION` limits — and returns what is wrong
- * with it, readable by the user, or null when it is valid.
+ * Returns what is wrong with a sign-up body, as the message the register page
+ * shows, or null when it is valid. It checks the shape, the email's form, and
+ * the username and password against the `VALIDATION` limits. Whether the name,
+ * the email or the invite is taken is `createUser`'s and `claimInvite`'s check.
  */
 export function validateRegisterUserRequest(obj: unknown): string | null {
   if (
@@ -71,8 +78,10 @@ export function validateRegisterUserRequest(obj: unknown): string | null {
 }
 
 /**
- * Checks whether `obj` is a valid {@link UpdateUserRequest}: each field it
- * carries well-formed, and within the `VALIDATION` limits.
+ * Checks whether `obj` is a valid {@link UpdateUserRequest}, for
+ * `PATCH /api/users/me`. Every field is optional, but each one present must be
+ * well-formed and within the `VALIDATION` limits. The username's limits here
+ * are not those of sign-up, which the route never lets it change anyway.
  */
 export function isUpdateUserRequest(obj: unknown): obj is UpdateUserRequest {
   if (!obj || typeof obj !== "object") return false;