Route-level code splitting for faster mobile first paint (#106) #113

Merged
steve merged 2 commits from feat/code-splitting into main 2026-07-22 06:18:23 +00:00
2 changed files with 49 additions and 18 deletions
Showing only changes of commit 79df0df53f - Show all commits
+41 -17
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@@ -1,4 +1,4 @@
import { lazy } from 'react'
import { lazy, type ComponentType } from 'react'
import {
createRootRouteWithContext,
createRoute,
@@ -12,28 +12,52 @@ import { RouteError } from '@/components/RouteError'
import { LoginPage } from '@/pages/LoginPage'
import { GardensPage } from '@/pages/GardensPage'
import { meQueryOptions } from '@/lib/auth'
import { queryClient } from '@/lib/queryClient'
import { safeRedirectPath } from '@/lib/redirect'
import { getLastGardenId } from '@/lib/lastGarden'
// Lazily load a page by its named export, with recovery for the stale-chunk
// problem. A push to main redeploys, so a still-open app references chunk hashes
// the server has just replaced; that import 404s and React.lazy MEMOIZES the
// rejection, so RouteError's "Try again" (router.invalidate) can never recover —
// the user is stuck until a manual hard reload. On the first such failure we
// reload once (fetching the fresh index + hashes); a session flag stops a reload
// loop, and a success clears it so a later genuine failure can reload again.
function lazyPage<M, K extends keyof M>(load: () => Promise<M>, name: K) {
return lazy(async () => {
try {
const mod = await load()
try {
sessionStorage.removeItem('pansy:chunk-reload')
} catch {
/* storage unavailable — fine */
}
return { default: mod[name] as ComponentType }
} catch (err) {
try {
if (!sessionStorage.getItem('pansy:chunk-reload')) {
sessionStorage.setItem('pansy:chunk-reload', '1')
window.location.reload()
return await new Promise<{ default: ComponentType }>(() => {}) // hold for the reload
}
} catch {
/* storage unavailable — fall through to surface the error */
}
throw err // already reloaded once (or can't); let the error boundary show it
}
})
}
// Code-split the heavier / deeper routes so a phone on cell data doesn't download
// the whole app (notably the canvas editor with its gesture + geometry deps)
// before the first screen paints. Login and the gardens list — the entry points —
// stay eager to avoid a fallback flash on landing; AppShell wraps the Outlet in a
// Suspense boundary for the rest.
const GardenEditorPage = lazy(() =>
import('@/pages/GardenEditorPage').then((m) => ({ default: m.GardenEditorPage })),
)
const PublicGardenPage = lazy(() =>
import('@/pages/PublicGardenPage').then((m) => ({ default: m.PublicGardenPage })),
)
const PlantsPage = lazy(() => import('@/pages/PlantsPage').then((m) => ({ default: m.PlantsPage })))
const SettingsPage = lazy(() =>
import('@/pages/SettingsPage').then((m) => ({ default: m.SettingsPage })),
)
const RegisterPage = lazy(() =>
import('@/pages/RegisterPage').then((m) => ({ default: m.RegisterPage })),
)
import { queryClient } from '@/lib/queryClient'
import { safeRedirectPath } from '@/lib/redirect'
import { getLastGardenId } from '@/lib/lastGarden'
const GardenEditorPage = lazyPage(() => import('@/pages/GardenEditorPage'), 'GardenEditorPage')
const PublicGardenPage = lazyPage(() => import('@/pages/PublicGardenPage'), 'PublicGardenPage')
const PlantsPage = lazyPage(() => import('@/pages/PlantsPage'), 'PlantsPage')
const SettingsPage = lazyPage(() => import('@/pages/SettingsPage'), 'SettingsPage')
const RegisterPage = lazyPage(() => import('@/pages/RegisterPage'), 'RegisterPage')
interface RouterContext {
queryClient: QueryClient
+8 -1
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@@ -39,7 +39,14 @@ export default defineConfig(({ mode }) => {
// routes are code-split separately via React.lazy (router.tsx), which is
// where the real first-paint win is.
manualChunks(id) {
Review

🟠 manualChunks forces editor-only deps (@use-gesture, geometry) into the eager vendor chunk, defeating the first-paint split for those libraries

performance · flagged by 1 model

  • web/vite.config.ts:41-43 — the gesture/geometry deps the PR wants off the first-paint path are actually pulled into it. The manualChunks(id) function unconditionally returns 'vendor' for every node_modules module, and that vendor chunk is on the critical path for every route (including the eager /login and /gardens). I verified that @use-gesture/react (the dep the PR description names as the biggest surface to keep lazy) is only referenced from `web/src/editor/useView…

🪰 Gadfly · advisory

🟠 **manualChunks forces editor-only deps (@use-gesture, geometry) into the eager vendor chunk, defeating the first-paint split for those libraries** _performance · flagged by 1 model_ - **`web/vite.config.ts:41-43` — the gesture/geometry deps the PR wants off the first-paint path are actually pulled *into* it.** The `manualChunks(id)` function unconditionally returns `'vendor'` for **every** `node_modules` module, and that vendor chunk is on the critical path for *every* route (including the eager `/login` and `/gardens`). I verified that `@use-gesture/react` (the dep the PR description names as the biggest surface to keep lazy) is only referenced from `web/src/editor/useView… <sub>🪰 Gadfly · advisory</sub>
return id.includes('node_modules') ? 'vendor' : undefined
if (!id.includes('node_modules')) return undefined
// Editor-only libs (the gesture engine) ride with the lazy editor
// chunk instead of the eager vendor one, so the first paint doesn't
// pay for code only the canvas needs. Everything else — react, tanstack
// and the rest — stays in ONE vendor chunk; splitting react-dom out
// reorders its init across chunks and breaks React 19 at load.
if (id.includes('@use-gesture')) return undefined
return 'vendor'
},
},
},