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/remote/image-proxy.ts

@@ -1,17 +1,21 @@
 /**
- * The image proxy's fetch and cache: remote thumbnails are served through
- * this site, so viewers' browsers never contact the hosts.
+ * Fetches and caches the remote images `GET /api/proxy-image` serves. The
+ * frontend routes a thumbnail through it when the image is on plain http,
+ * which an https page would block, or when loading it directly failed, often
+ * to hotlink protection.
  *
  * @module
  */
 
 import { fetchWithTimeout } from "./fetch.ts";
 
-/** An image fetched for the proxy. */
+/**
+ * Returned to `GET /api/proxy-image` by {@link fetchProxiedImage}, which sends
+ * it back under `contentType`.
+ */
 export interface ProxiedImage {
-  /** The image's bytes. */
   bytes: Uint8Array;
-  /** The image's MIME type, as its host sent it. */
+  /** One of the raster types, without parameters. */
   contentType: string;
 }
 
@@ -26,14 +30,12 @@ const PROXYABLE_IMAGE_TYPES = new Set([
   "image/vnd.microsoft.icon",
 ]);
 
-/** How long a proxied image is served from the cache. */
 const IMAGE_CACHE_TTL_MS = 24 * 60 * 60 * 1000;
-/** The cache's size bound, in image bytes. */
 const IMAGE_CACHE_MAX_BYTES = 32 * 1024 * 1024;
 /**
- * Proxied images, by URL: every viewer of a feed asks for the same thumbnails,
- * which were fetched from their hosts again for each one. Bounded by total
- * size; the least recently used go first. Map order is recency order.
+ * Proxied images, by URL, since every viewer of a feed asks for the same
+ * thumbnails. The least recently used go first, and the Map's order is that
+ * of use.
  */
 const imageCache = new Map<
   string,
@@ -51,7 +53,7 @@ function readImageCache(
     imageCacheBytes -= hit.bytes.byteLength;
     return undefined;
   }
-  imageCache.set(url, hit); // most recently used
+  imageCache.set(url, hit); // Moves it to the end: most recently used.
   return hit;
 }
 
@@ -77,7 +79,7 @@ function writeImageCache(
   imageCacheBytes += bytes.byteLength;
 }
 
-/** Forgets every proxied image (for the tests). */
+/** Empties the cache, for the tests' reset between cases. */
 export function clearImageCache(): void {
   imageCache.clear();
   imageCacheBytes = 0;
@@ -85,9 +87,11 @@ export function clearImageCache(): void {
 
 /**
  * Returns the image at `url`, from the cache or else from its host; null when
- * the host answers with something that isn't a raster image of 5 MB at most.
+ * the host answers with anything but a raster image of 5 MB at most. The route
+ * checks `url` with `isValidHttpUrl` first.
  *
- * @throws {Error} When the host can't be reached (see {@link fetchWithTimeout}).
+ * @throws {Error} When the host can't be reached, as
+ * {@link fetchWithTimeout} reports it.
  */
 export async function fetchProxiedImage(
   url: string,
@@ -96,9 +100,8 @@ export async function fetchProxiedImage(
   if (cached) return cached;
 
   const res = await fetchWithTimeout(url, 8000);
-  // Raster formats only. The bytes go out under this site's origin, so an
-  // SVG (which can carry script) or anything else a browser might execute
-  // would run with the app's origin if opened directly.
+  // Raster formats only: the bytes go out under this site's origin, where an
+  // SVG, which can carry script, would run if opened directly.
   const contentType = (res.headers.get("content-type") ?? "")
     .split(";")[0].trim().toLowerCase();
   if (!PROXYABLE_IMAGE_TYPES.has(contentType)) {
@@ -106,7 +109,7 @@ export async function fetchProxiedImage(
     return null;
   }
 
-  const MAX_SIZE = 5 * 1024 * 1024; // 5 MB
+  const MAX_SIZE = 5 * 1024 * 1024;
   const contentLength = Number(res.headers.get("content-length") ?? "0");
   if (contentLength > MAX_SIZE) {
     await res.body?.cancel();