Migrate Dapp

migrate-dapp

Playbook for absorbing a standalone Decentraland dapp into this SPA. Mirrors how whats-on, blog, jump, social, and cast were brought in. Heavy tier only — every dapp ported so far needs Redux + RTK Query.

Overview

The migration is mechanical once decisions are made. It's never "copy code 1:1" — the source dapp ships its own Web3 stack, navbar/footer, and provider tree, and ALL of those get dropped. The user-facing UI (cards, lists, modals) stays.

Decisions to take with the user FIRST (AskUserQuestion)

Don't guess these — they shape the code.

1. Path: source uses some basename (/social, /jump, /blog, /cast). What public path do we mount under in sites? Singular vs plural matters (/community/:id vs /communities/:id). Verify against the production sitemap, not just the source router. If the source has sub-paths/tabs, ask whether they should be URL-driven or internal state.
2. Auth: the source almost certainly imports wagmi, magic-sdk, thirdweb, decentraland-connect (or in cast2's case, an anonymous + token‑in‑URL flow). Sites drops Web3 — useAuthIdentity (localStorage SSO) + signedFetch for signed mutations, OR keep the source's anonymous flow if that's how the backend already works. Confirm with the user. Unauthenticated CTAs that need identity redirect to the global SSO via redirectToAuth(path, queryParams).
3. Sign-in callback: reuse the global /sign-in lightweight page (already exists in src/App.tsx). Don't port the source's own SignInRedirect.
4. i18n locales: source typically ships en/es/zh. Sites needs all 6 (en, es, fr, ja, ko, zh) per rule 9. Ask: hand-translate fr/ja/ko now, copy English placeholders, or block the PR on localization team.
5. Navbar item: ask explicitly — don't add LandingNavbar entries unprompted.

Use AskUserQuestion for these in plan mode. Cite the trade-offs (e.g. dropping Web3 = ~580–780KB saved, mutations require pre-existing identity).

Phase 1: explore (plan mode)

Launch up to 3 Explore agents in parallel:

• One to map the source dapp: routes, RTK Query clients, types, page components, helpers, i18n keys, segment events, auth flow, tests.
• One to refresh the sites patterns: src/services/cmsClient.ts, src/features/cms/cms.client.ts, src/shells/store.ts, src/shells/DappsShell.tsx, src/components/Layout/Layout.helpers.ts, src/utils/signedFetch.ts, src/hooks/useAuthIdentity.ts, src/hooks/useBlogPageTracking.ts, src/utils/authRedirect.ts, src/features/profile/profile.client.ts, src/features/cms/useInfiniteBlogPosts.ts, env JSONs.
• Optional third agent for path resolution if the source has a basename quirk.

Then read the actual files (not just agent summaries) for: source *.client.ts, source *.types.ts, source page components, source i18n locales (all of them — you'll port them).

Files to add (heavy tier)

Files to modify

Design system — use decentraland-ui2, NOT custom assets/deps (paid in blood, cast2 PR #403)

Every cast2 source dependency below was a wasted install + extra cleanup commit when porting. Hit the design-system primitives FIRST, drop the source assets:

• No @emotion/react or @emotion/styled direct deps. Sites resolves both transitively through decentraland-ui2 → @mui/material → @emotion/*. Importing keyframes from @emotion/react works without a direct entry in package.json. NEVER npm install @emotion/react @emotion/styled — npm uninstall immediately if you see the source dapp pinning them.
• No classnames dep. Sites uses styled-components everywhere; conditional styling goes in styled('div', { shouldForwardProp })<{ $variant: ... }>(({ $variant }) => ({ ... })). If the source uses classnames, refactor to styled props during the port — don't carry the dep.
• Replace static logo.png (or any DCL wordmark/brand image) with <Logo size="huge" /> from decentraland-ui2. Sizes: 'normal' | 'large' | 'huge' | 'massive'. Used by PressPage, DownloadSuccess, etc.
• Replace static onboarding/landing backgrounds with <AnimatedBackground variant="absolute" /> from decentraland-ui2. Render it as a sibling of your content inside a position: relative; isolation: isolate container — no PNG fallback. Existing usages: Home/WhatsOn, Home/ComeHangOut, Invite/InviteHero, Support/ChatCTABanner, Report/ReportSuccess.
• Replace hardcoded colours with dclColors.* from decentraland-ui2 whenever the match is direct: 'white' → dclColors.neutral.white, '#1a1a1a' → dclColors.neutral.softBlack1, '#000' → dclColors.neutral.black. The palette also exposes base.primary*, brand.{ruby,violet,...}, neutral.gray0..gray5. Brand-specific gradients (#210A35, #FF2D55-into-#FF6B82) and rgba overlays stay verbatim.
• Static avatar fallback PNG (avatar.png) → deterministic seeded background via getAvatarBackgroundColor + getDisplayName from src/utils/avatarColor.ts (ADR-292 NameColorHelper). The cast Avatar component already does this — call sites pass name, imageUrl?, ethAddress? and the component picks the seeded colour + initial when there's no image. Same pattern as the in-world client, hue stays consistent across surfaces.
• Compress any source PNG > 500 KB to WebP before importing. cwebp -q 70 input.png -o output.webp typically gives 95–98% reduction (background_watcher.png 2.5 MB → .webp 88 KB on cast2). Update the import extension and delete the PNG.

Gotchas (paid in blood)

• decentraland-ui2 does NOT export muiIcons or a JumpIn modalProps.title/description/buttonLabel API (current dep: ^3.13.0). Source dapps using these need rewrites: import CheckIcon from '@mui/icons-material/Check', and explorer launching goes through the shared src/hooks/useLaunchExplorer.ts hook (launchDesktopApp + ui2 DownloadModal fallback — JumpInButton and EditProfileButton both consume it).
• react-router v7 quirk: a child <Route path="*" /> does NOT match the parent's empty trailing path. If /cast (with no children) renders blank but /cast/anything shows the catch-all, add <Route index element={<NotFoundPage />} /> alongside the wildcard inside the parent route block (cast2 PR #403, commit 306600c).
• Reuse existing components first. Check LiveNowCardItem (whats-on event card), EventDetailModal, useEventDetailModal before writing your own. Source dapps often render their own card — DRY by mapping the dapp's event shape into EventEntry and reusing the whats-on card. The social migration ended up doing exactly this.
• decentraland-ui2 is ESM-only and Jest can't transform it. UI specs MUST jest.mock('decentraland-ui2', ...) AND jest.mock('./<Component>.styled', ...). See src/components/social/CommunityDetail/MembersList/MembersList.spec.tsx for the forwardRef-with-prop-filtering pattern. Don't try to make ts-jest transform decentraland-ui2 — that's the wrong layer.
• import.meta.env in src/config/index.ts doesn't compile under ts-jest. Specs that touch getEnv() transitively MUST jest.mock('../../config/env', () => ({ getEnv: () => 'https://...' })).
• decentraland-crypto-fetch references global Request, missing in older jsdom. The base-client smoke spec must jest.mock('decentraland-crypto-fetch', () => ({ signedFetchFactory: () => async () => new Response('{}') })) BEFORE import { <dapp>Client }.
• No top-level throws in shell-reachable files (rule 16). All env getters are lazy (getXxxUrl() throws on call, not on import). One throw at module top crashes the whole DappsShell chunk.
• No import { store } in endpoint files (rule 17). Use onQueryStarted for dispatch, endpoint.select()(state) for reads.
• Mutations must be immutable (rule 22). When enriching cached responses, build a Map/spread new objects — never mutate draft.data.results[i] keys directly outside of updateQueryData.
• ?action=... auto-execute pattern: when the CTA redirects unauthenticated users to SSO, append ?action=join|requestToJoin. After auth, the page re-renders with identity AND the action param, runs the mutation once via useEffect + executedActionRef, then strips the param via navigate({ search: '' }, { replace: true }). See CommunityDetail.tsx.
• HelmetProvider must wrap the lazy heavy chunk. The DappsShell already does this post-social migration. New heavy pages don't need their own provider.
• Source dapps use getRandomRarityColor(theme) (Math.random per render) — do NOT port this directly. Make it deterministic by seed (e.g. address) so avatars don't flicker on rerender. See getRarityColor(theme, seed) in src/features/communities/communities.helpers.ts.
• Map RTK Query errors to i18n keys, not raw server strings (rule 10). When the dapp surfaces error UX (e.g. "no active stream", "not authorized"), build a small helper that switches on err.status (number for HTTP, 'FETCH_ERROR'/'TIMEOUT_ERROR'/'PARSING_ERROR' for transport) and returns a stable i18n key. console.error(err) for debugging, setError(t(getCastErrorKey(err, ctx))) for the UI. See src/features/cast2/cast2.errors.ts.
• Watch out for env-key renames during merge with master. While you're working in a long-lived branch, parallel dapp PRs can land env keys that collide with yours (cast2 had WORLDS_CONTENT_URL, social/storage already merged WORLDS_CONTENT_SERVER_URL). After every git merge origin/master, grep for any getEnv('FOO') that no longer exists in src/config/env/*.json and rename. The DappsShell preconnect spec is a fast canary — it asserts the actual key.

Verification (in order — no skipping)

1. npm run format
2. npm run lint:fix — re-run if it auto-fixed
3. npm run lint:pkg
4. npm run build — catches stricter TS than tsc --noEmit and surfaces missing decentraland-ui2 exports
5. npm test — must include the smoke test asserting the new reducer is registered (rule 6)
6. npm run preview + Chrome DevTools MCP for the route. Check: signed-in vs not, public vs private/gated, mobile breakpoint vs desktop, infinite scroll fires fetches, navbar clearance, Helmet title, page tracking fires AFTER title resolves.
7. i18n parity one-liner before pushing:

   for f in en es fr ja ko zh; do node -e "const j=require('./src/intl/$f.json'); if(!j.<namespace>?.<known_subkey>) throw new Error('$f missing'); console.log('$f ok')"; done
   

8. Run pr-review-toolkit:code-reviewer on git diff master...HEAD. Treat P0/P1 as blockers.

Out of scope by default (ask explicitly to add)

• Navbar item / nav menu wiring
• SEO rewrite for the new path (most absorbed dapps are auth-gated → no SEO benefit)
• Vite manualChunks tweaks (current chunks already cover most patterns)
• Deleting the standalone source repo (separate operation, after merge)
• Web3 in-page wallet connect (explicitly dropped)

Reference: prior migrations

• whats-on — events flow + admin
• blog — Contentful + cms-server full-text search
• jump — launcher deep-link handler (places + events + worlds)
• social — communities (feat/migrate-social-dapps branch — canonical for the standard auth+RTK shape)
• cast — LiveKit streaming (PR #403 — canonical for: anonymous + token-in-URL auth, <AnimatedBackground> + <Logo> swap, dclColors/WebP cleanup, react-router v7 index-route fix, RTK Query error → i18n mapping)
• storage — storage-service-site (subgraph ownership lookups, scene/players queries; uses storageClient + subgraphClient base APIs)
• reels — in-game camera screenshots. Layout-less lightweight tier (the only absorbed dapp not under DappsShell) — fullscreen UX is the whole point, so reels routes are placed BEFORE the <Layout /> block in src/App.tsx and use a useSyncExternalStore-style client (no Redux)
• report — community report flow. Lightweight (no RTK Query, no Redux); helpers + types only under src/features/report/