Build the TaskFlow Frontend Shell Apply routing, layouts, server/client composition, accessible navigation, and scoped styling to the first real TaskFlow interface.
Build the First TaskFlow Frontend Shell This book turns the concepts into one coherent mini-application. It remains intentionally frontend-only. We use static sample content because Phase 04-06 will introduce the backend and HTTP boundary.
Target experience • A root layout with TaskFlow branding and primary navigation. • Home dashboard route with a welcome section and summary cards. • Projects route with static project previews. • Settings route with a small interactive preference control isolated as a Client Component. • Responsive CSS Modules/global styles. • Metadata and basic accessible structure.
Step 1 - Root layout
// src/app/layout.tsx
import type { Metadata } from "next";
import Link from "next/link";
import "./globals.css";export const metadata: Metadata = { title: "TaskFlow", description: "Project and task management for focused teams", };
export default function RootLayout({ children }: Readonly<{ children: React.ReactNode }>) {
return (
<html lang="en">
<body>
<header>
<Link href="/">TaskFlow</Link>
<nav aria-label="Primary navigation">
<Link href="/projects">Projects</Link>
<Link href="/settings">Settings</Link>
</nav>
</header>
<main>{children}</main>
</body>
</html>
);
}The layout defines document shell and shared navigation. It does not contain application state or business rules.
Step 2 - Home page
// src/app/page.tsx
export default function HomePage() {
return (
<section>
<p>TaskFlow</p>
<h1>Keep work visible and moving.</h1>
<p>Projects, tasks, ownership, and progress will grow here throughout the course.</p>
</section>
);
}// src/app/projects/page.tsx
const projects = [
{ id: 1, name: "Website refresh", status: "Active" },
{ id: 2, name: "Inventory rollout", status: "Planning" },
];export default function ProjectsPage() {
return (
<section>
<h1>Projects</h1>
<div>
{projects.map((project) => (
<article key={project.id}>
<h2>{project.name}</h2>
<p>{project.status}</p>
</article>
))}
</div>
</section>
);
}The array is intentionally local sample data. We are practicing rendering and component composition, not pretending we already have persistence.
Step 4 - Isolate one interactive control // src/app/settings/density-toggle.tsx "use client";
import { useState } from "react";export function DensityToggle() {
const [compact, setCompact] = useState(false);return ( <button onClick={() => setCompact((value) => !value)}> Density: {compact ? "Compact" : "Comfortable"} </button> ); }
Then import DensityToggle into settings/page.tsx. The page remains a Server Component; only the interactive control becomes client-side.
Step 5 - Styling Create globals.css for base document variables and layout. Use CSS Modules for cards/navigation-specific styles as the UI grows. Do not turn globals.css into a giant unscoped component stylesheet.
Step 6 - Verify all routes http://localhost:3000/ http://localhost:3000/projects http://localhost:3000/settings
Navigate using the UI links, refresh each route directly, and verify there are no console errors.
Step 7 - Lint and build From taskflow root, use package filtering so the command demonstrates the monorepo model:
pnpm --filter web lint
pnpm --filter web buildIf the package name differs, use the actual name from apps/web/package.json.
/ /projects /settings
Settings + client Home page Projects page island
Figure 1 - One Next.js application now owns routing and presentation while the API boundary remains intentionally empty
Do not add these yet • No Supabase client. • No Prisma. • No NestJS calls. • No TanStack Query. • No authentication provider. • No global store. • No fake repository abstraction.
Each of those technologies enters later because a specific architectural problem appears.
Definition of done • Three routes render through the shared layout. • At least one small Client Component demonstrates browser interaction. • No unnecessary use client appears on pages/layouts. • Styling is readable and scoped. • Keyboard navigation reaches links/buttons visibly. • Lint and production build pass.
Build the TaskFlow Frontend Shell matters because it changes a real boundary in TaskFlow. The goal is to understand the inputs, owner, observable output, and failure modes before adding more abstraction.
Restate the goal of “Build the TaskFlow Frontend Shell” as one observable behavior. Write the success signal before touching code.
Trace the boundary map: route data → UI state → component tree → interaction → accessible feedback. 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 navigable TaskFlow web shell with route groups/layouts, server-first composition, selective client interactivity, and verified environment handling.. 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.
if (query.isPending) return <TaskSkeleton />;
if (query.isError) return <TaskError retry={query.refetch} />;
if (!query.data.length) return <EmptyTasks />;
return <TaskTable tasks={query.data} />;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.
Return to the nearest observable boundary: input, network, process log, database, or rendered UI. Compare actual evidence with the predicted path.
Change one variable at a time and reproduce the original failure after the fix; otherwise you have correlation, not diagnosis.
Without copying the final source, create a second small scenario that applies “Build the TaskFlow Frontend Shell” to a different TaskFlow resource or input. Write the acceptance criteria first, implement it, and provide the evidence that each criterion is satisfied.
Generate the web app in the monorepo and verify the development server from the correct workspace.
Use the smallest change that demonstrates this lesson. Stop after it works and capture evidence.Leaking secrets through NEXT_PUBLIC variables
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.