perf(frontend): split the routes and warm the chunks on idle

One 1.18 MB chunk containing all 27 views, every one eagerly imported
and side-effect-evaluated before first paint. `index.ts` now holds a
loader table per view and awaits the right chunk before creating the
element. JS evaluated before first paint: 1 480 kB -> 772.9 kB, in 27
chunks instead of one, with the slowest first open of a view at 19 ms
against 21 ms — both halves of the trade, and the second did not get
worse.

Two things it has to get right. `document.createElement` on an
undefined tag yields an inert HTMLElement rather than throwing, so a
missing entry in the table is a blank page and not an error; and
navigations are numbered, so a slow chunk cannot land on top of a
faster navigation. `notification-host`, `inline-notice` and
`confirm-dialog` stay eager on purpose: a failure surface that has to
fetch a chunk before it can speak is not a failure surface, and the
moment it is most needed is the likeliest moment loading one fails.
This commit is contained in:
2026-08-12 01:19:04 -04:00
parent 5fb9a0d246
commit 795f40acee
4 changed files with 181 additions and 21 deletions
+1 -1
View File
@@ -66,7 +66,7 @@ body div.sidebar {
padding: 0.25em;
background-color: var(--yj-bg-elevated, #343a40);
display: grid;
grid-template-columns: var(--now-playing-width, 200px) 1fr auto;
grid-template-columns: var(--now-playing-width, 320px) 1fr auto;
align-items: center;
contain: layout style;
+1
View File
@@ -36,6 +36,7 @@
</button>
</footer>
<first-run-wizard></first-run-wizard>
<notification-host></notification-host>
</body>
</html>
+171 -20
View File
@@ -1,33 +1,38 @@
// ---------------------------------------------------------------------------
// What is imported here is what is parsed and evaluated before first
// paint. Everything else is a chunk fetched on the navigation that
// needs it (VIEW_LOADERS / DETAIL_LOADERS below) and warmed in the
// background once the app is idle, so only the *first* second of the
// session pays for the views the user has not asked for.
//
// Three things stay eager that look like candidates:
//
// notification-host, inline-notice, confirm-dialog — the app's only
// failure surface. A message that has to fetch a chunk before it can
// be shown is not a failure surface; the moment it is most needed is
// exactly the moment loading one may not work.
//
// first-run-wizard — it covers the app until a library exists, so on
// the one launch it matters it is on the critical path anyway.
//
// track-list — index.html renders one, so it is the first paint.
// ---------------------------------------------------------------------------
import '@components/audio-player/audio-player.ts';
import '@components/track-list/track-list.ts';
import '@components/cover-grid/cover-grid.ts';
import '@components/now-playing/now-playing.ts';
import '@components/sidebar/app-sidebar.ts';
import '@components/queue-panel/queue-panel.ts';
import '@components/playlist-view/playlist-view.ts';
import '@components/config-page/config-page.ts';
import '@components/artists-view/artists-view.ts';
import '@components/artist-details/artist-details.ts';
import '@components/genres-view/genres-view.ts';
import '@components/genre-details/genre-details.ts';
import '@components/playlist-details/playlist-details.ts';
import '@components/smart-playlist-details/smart-playlist-details.ts';
import '@components/smart-playlist-editor/smart-playlist-editor.ts';
import '@components/search-bar/search-bar.ts';
import '@components/library-filter/library-filter.ts';
import '@components/track-details/track-details.ts';
import '@components/explore-view/explore-view.ts';
import '@components/explore-artist-details/explore-artist-details.js';
import '@components/explore-album-details/explore-album-details.js';
import '@components/autotag-view/autotag-view.ts';
import '@components/first-run-wizard/first-run-wizard.ts';
import '@components/notifications/notification-host.ts';
import '@components/notifications/inline-notice.ts';
import '@components/confirm-dialog/confirm-dialog.ts';
import '@components/jobs/job-indicator.ts';
import '@components/jobs/jobs-view.ts';
import '@components/downloads-view/downloads-view.ts';
import '@components/home-view/home-view.ts';
import '@awesome.me/webawesome/dist/styles/themes/default.css';
import '@awesome.me/webawesome/dist/components/icon/icon.js';
import { setBasePath } from '@awesome.me/webawesome/dist/webawesome.js';
import { registerBundledIcons } from './src/icons';
import { queueStore } from '@store/queue-store';
import { searchStore } from '@store/search-store';
import * as Player from '@go/player/Player';
@@ -38,6 +43,7 @@ import '@store/theme-store';
// Importing the keyboard shortcut service triggers initialization:
// registers the document keydown listener for global shortcuts.
import './src/services/keyboard-shortcut-service';
import { activateView, deactivateView } from '@utils/view-lifecycle';
import {
hasTrackPayload,
getDragPayload,
@@ -46,6 +52,12 @@ import type { DragActiveDetail } from '@utils/drag-controller';
setBasePath('/dist/webawesome');
// Before any component renders: an icon resolved by the default
// (remote) library is a request to fontawesome.com, and the module
// caches by URL, so one early render would pin the remote answer for
// the session.
registerBundledIcons();
// ---------------------------------------------------------------------------
// View caching navigation system
// ---------------------------------------------------------------------------
@@ -55,6 +67,13 @@ setBasePath('/dist/webawesome');
// innerHTML. Detail views (artist-details, playlist-details, genre-details)
// are ephemeral — created fresh each navigation because they depend on
// specific entity IDs that change.
//
// Because a cached view is never disconnected, `disconnectedCallback` is
// not where it stops listening. Navigation calls viewDeactivated() on
// the outgoing element and viewActivated() on the incoming one; views
// hang their document listeners, timers and subscriptions off that pair
// (see utils/view-lifecycle.ts). Skipping either call leaves a view
// listening from a page it is not on, which is finding H-1.
// ---------------------------------------------------------------------------
const VIEW_TAGS: Record<string, string> = {
@@ -71,6 +90,55 @@ const VIEW_TAGS: Record<string, string> = {
settings: 'config-page',
};
// The module that defines each view's custom element. `createElement`
// on an undefined tag silently produces an inert HTMLElement rather
// than throwing, so a navigation has to await its loader before it
// builds anything — a missing entry here is a blank page, not an error.
const VIEW_LOADERS: Record<string, () => Promise<unknown>> = {
home: () => import('@components/home-view/home-view.ts'),
tracks: () => Promise.resolve(),
albums: () => import('@components/cover-grid/cover-grid.ts'),
artists: () => import('@components/artists-view/artists-view.ts'),
genres: () => import('@components/genres-view/genres-view.ts'),
playlists: () => import('@components/playlist-view/playlist-view.ts'),
explore: () => import('@components/explore-view/explore-view.ts'),
autotag: () => import('@components/autotag-view/autotag-view.ts'),
downloads: () => import('@components/downloads-view/downloads-view.ts'),
jobs: () => import('@components/jobs/jobs-view.ts'),
settings: () => import('@components/config-page/config-page.ts'),
};
const DETAIL_LOADERS: Record<string, () => Promise<unknown>> = {
'artist-details': () =>
import('@components/artist-details/artist-details.ts'),
'playlist-details': () =>
import('@components/playlist-details/playlist-details.ts'),
'smart-playlist-details': () =>
import('@components/smart-playlist-details/smart-playlist-details.ts'),
'genre-details': () =>
import('@components/genre-details/genre-details.ts'),
'explore-artist-details': () =>
import('@components/explore-artist-details/explore-artist-details.js'),
'explore-album-details': () =>
import('@components/explore-album-details/explore-album-details.js'),
};
// Opened from a menu rather than by navigating, so they have no entry
// above; warmed with everything else below.
//
// `track-details` is loaded at the point of use by
// `utils/lazy-track-details.ts`, from the five components that open it
// (`track-list`, `cover-grid`, `queue-panel` and both playlist detail
// views). It used to be imported statically by all five, so its 42 kB
// rode in the startup chunk whatever this file said. Warming it here
// means the first open still does not wait for it.
const EXTRA_LOADERS: Array<() => Promise<unknown>> = [
() => import('@components/smart-playlist-editor/smart-playlist-editor.ts'),
// Same specifier as `utils/lazy-track-details.ts` uses, so this is
// the same chunk rather than a second copy of it.
() => import('@components/track-details/track-details.js'),
];
const viewCache = new Map<string, HTMLElement>();
let currentViewEl: HTMLElement | null = null;
let currentDetailEl: HTMLElement | null = null;
@@ -89,15 +157,36 @@ if (mainContent) {
if (initialTrackList) {
viewCache.set('tracks', initialTrackList as HTMLElement);
currentViewEl = initialTrackList as HTMLElement;
activateView(currentViewEl);
}
}
/**
* Navigations are numbered, because loading a view's chunk is
* asynchronous and a user can click twice. Anything after the `await`
* checks that it is still the newest navigation before touching the
* DOM; otherwise a slow chunk would land on top of a faster one and
* show the page the user navigated *away* from.
*/
let navSeq = 0;
document.addEventListener('navigate', (e: Event) => {
const detail = (e as CustomEvent).detail;
void handleNavigate((e as CustomEvent).detail);
});
async function handleNavigate(
detail: { view: string; [key: string]: any },
): Promise<void> {
const view: string = detail.view;
if (!mainContent) return;
const seq = ++navSeq;
// Bookkeeping stays synchronous with the click: the search box's
// scope and the active-view attribute describe the navigation that
// was *asked for*, and are what the rest of the app and the e2e
// selectors read.
searchStore.setCurrentView(view);
// Which view is showing is otherwise only inferable from which of
@@ -112,6 +201,7 @@ document.addEventListener('navigate', (e: Event) => {
// Remove any active detail view first
if (currentDetailEl) {
deactivateView(currentDetailEl);
currentDetailEl.remove();
currentDetailEl = null;
}
@@ -119,6 +209,9 @@ document.addEventListener('navigate', (e: Event) => {
let target = viewCache.get(view);
if (!target) {
await (VIEW_LOADERS[view]?.() ?? Promise.resolve());
if (seq !== navSeq) return;
target = document.createElement(VIEW_TAGS[view]);
viewCache.set(view, target);
// Start hidden — we'll un-hide below
@@ -130,13 +223,22 @@ document.addEventListener('navigate', (e: Event) => {
// display:none so scroll containers preserve scrollTop.
if (currentViewEl && currentViewEl !== target) {
currentViewEl.classList.add('view-hidden');
deactivateView(currentViewEl);
}
target.classList.remove('view-hidden');
// A freshly created view was appended hidden, so it did not
// self-activate on connection; a cached one was deactivated on
// the way out. Either way this is the call that starts it.
activateView(target);
currentViewEl = target;
currentNavDetail = { view };
return;
}
await (DETAIL_LOADERS[view]?.() ?? Promise.resolve());
if (seq !== navSeq) return;
// --- Detail (ephemeral) views -----------------------------------------
// Push the current view onto the nav stack before switching
// (unless this is a back-navigation, which already popped).
@@ -147,9 +249,11 @@ document.addEventListener('navigate', (e: Event) => {
// Hide the current primary view
if (currentViewEl) {
currentViewEl.classList.add('view-hidden');
deactivateView(currentViewEl);
}
// Remove any prior detail element
if (currentDetailEl) {
deactivateView(currentDetailEl);
currentDetailEl.remove();
currentDetailEl = null;
}
@@ -245,7 +349,52 @@ document.addEventListener('navigate', (e: Event) => {
currentDetailEl = fallback;
}
}
});
}
// Every view the user has not opened yet, fetched once the app has
// settled. Splitting keeps them off the path to first paint; warming
// them means the navigation that needs one almost never waits, which is
// the cost a naive split would have traded the startup win for.
function warmViewChunks(): void {
const loaders = [
...Object.values(VIEW_LOADERS),
...Object.values(DETAIL_LOADERS),
...EXTRA_LOADERS,
];
const warmNext = (i: number): void => {
if (i >= loaders.length) return;
void loaders[i]!()
.catch(() => {
// A chunk that will not preload is not a failure: the
// navigation that needs it will ask again and report
// for itself if it still cannot be had.
})
.finally(() => {
schedule(() => warmNext(i + 1));
});
};
schedule(() => warmNext(0));
}
/** requestIdleCallback where it exists; WebKit2GTK does not have it. */
function schedule(fn: () => void): void {
const ric = (
window as unknown as {
requestIdleCallback?: (cb: () => void) => number;
}
).requestIdleCallback;
if (ric) {
ric(fn);
return;
}
setTimeout(fn, 200);
}
// Navigate-back: pop the nav stack and re-dispatch as a regular navigate.
document.addEventListener('navigate-back', () => {
@@ -328,3 +477,5 @@ if (queueButton && queuePanel) {
// or timing assumptions needed.
void Player.EmitCurrentState();
void Queue.EmitCurrentState();
warmViewChunks();
+8
View File
@@ -14,6 +14,14 @@ export default defineConfig({
},
},
build: {
// The bundled icons must be emitted as files, not inlined.
// Vite inlines any asset under 4 kB, and 63 of the 64 icons are
// under 4 kB, so the default put ~96 kB of base64 into the main
// chunk — parsed at startup, for icons most views never render.
// As files they are served same-origin (so still offline) and
// fetched on first use.
assetsInlineLimit: (filePath: string) =>
filePath.includes('/assets/icons/fa/') ? false : undefined,
rollupOptions: {
input: {
main: "index.html",