Auth, Workspace and Cross-Tree Context Volume 06 - Professional Frontend | Phase 23
Context is a delivery mechanism, not automatically the owner Context is useful when many descendants need the same stable value and prop drilling would obscure the component API. But the value inside Context should still have a clear authoritative source.
Authentication • Supabase Auth owns the authenticated session.
• NestJS independently verifies access tokens.
• A React Context may expose convenience data to descendants, but it must not create a second authentication truth.
Workspace scope Business scope should remain reconstructable
URL Server Context UI /w/acme/tasks resolve workspace read resolved info header/menu
Avoid making a transient Context value the only record of which workspace the user is viewing.
For a multi-workspace business system, a deep-linkable route such as /w/[workspaceSlug]/tasks is often a stronger canonical owner than a transient Context-only selection. Context can then distribute the already-resolved workspace to deep UI children.
Do not put everything in one AppContext // Avoid a kitchen-sink context { user, tasks, filters, page, modalOpen, formDraft, selectedWorkspace, notifications, isLoading, error, ... }
• WorkspaceContext -> resolved current workspace metadata.
• Toast/notification provider -> transient cross-tree notifications.
• Theme provider -> presentation preference if the app supports it.
• Do not move query cache, RHF form state, or URL filters into those contexts.
Authentication answers who the request represents. Treating decoded or client-supplied identity as trusted is a security boundary failure.
Restate the goal of “Auth Session Workspace and Cross Tree Context” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: credentials/session → token → verification → trusted identity → protected operation. Mark the one boundary this lesson changes.
Inspect the current repository state and record the exact files, route, table, or runtime involved. Avoid creating an abstraction before you can name the existing owner.
Implement the smallest vertical slice. Add one coherent change, run the narrowest verification command, and read the output before continuing.
Connect the slice to TaskFlow’s phase artifact: A state ownership map for TaskFlow plus refactored examples removing redundant synchronized state.. Verify behavior from the outside as a user or API client would.
Create one controlled failure that is safe to reproduce. Predict the symptom first, capture evidence, locate the earliest broken boundary, then fix only that cause.
Close the reference and rebuild or explain the core change from memory. Record what you would monitor or test before trusting the same change in production.
const token = readBearerToken(request);
const claims = await verifier.verify(token);
request.user = {
id: claims.sub,
email: claims.email,
};Do not copy this as a finished answer. Predict what each boundary does, type the smallest useful slice, run it, then compare the result with your prediction.
Inspect whether a token exists, whether it is expired, which issuer/audience signed it, and what the API verifier expects.
Trust only verified server claims; never repair identity by accepting a client-sent user id.
Without copying the final source, create a second small scenario that applies “Auth Session Workspace and Cross Tree Context” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Create a diagram showing source of truth and allowed data flow for the screen.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.Global store used for all state categories
Predict the symptom before causing the failure. Then locate the earliest boundary where reality diverges from expectation.Why does this responsibility live here, what input does it trust, what output proves success, and what would go wrong if another layer owned it?
If your explanation is vague, repeat the boundary trace before moving on.Close the reference. Reproduce the core idea from memory or explain the exact request/data flow aloud. Then check your diff or notes for accidental shortcuts that bypass validation, authorization, error handling, or verification earned in earlier phases.