TL;DR: Frontend projects become messy because boundaries blur as they grow—coupling increases, shared state multiplies, and folder structure no longer matches the mental model. Fix it early by enforcing module boundaries, tracking state flow, and having someone own the structure.
It Didn’t Start Messy
Three months ago, your frontend codebase was clean. A few components, one store, maybe a utils folder. You could navigate it in your head. New features landed quickly. Tests were easy to write.
Then you shipped to more users. The business wanted more features. Your team grew. Now it’s a year later, and opening the codebase feels like walking into a cluttered storage room. A simple feature request takes days to understand where to start. Tests fail unpredictably. You’re hesitant to refactor anything because touching one file breaks three others.
This isn’t laziness. It’s not incompetence. It’s what happens when a small system is asked to grow without intentional structure.
Why Small Projects Feel Clean
Small frontend projects work fine with minimal structure. A 500-line component file? No problem. A global store that holds everything? Fine. All utilities dumped in a helpers.js? It works.
This happens because, at small scale, your mental model fits inside your head. You remember where things are. You see all the connections. You can make a change anywhere and trace the impact visually.
But mental models don’t scale. Around 5,000–10,000 lines of code, you hit a threshold. No single person can hold the entire structure in their head anymore. The implicit conventions that worked with two developers now confuse six. The folder structure stops matching how the system actually works.
That’s when things start degrading.
What Slowly Breaks as Projects Grow
Coupling Kills Refactoring
Early on, a component uses data from the store. The store mutation calls a utility function. The utility imports a constant from a component file. No one cares because the project is small.
As the codebase grows, this coupling compounds. You want to move a component to a new feature folder. But it’s tightly coupled to three other components and a store mutation. To move it, you have to move everything. Moving everything is risky. So you leave it.
Over time, the folder structure becomes a historical artifact, not a reflection of the actual system.
Shared State Becomes a Dumping Ground
Your Redux store started focused: user, auth, notifications. Then someone added tempFilters because a feature needed it. Then uiState because opening and closing panels was scattered. Then performanceMetrics, debugFlags, and a dozen other things.
The store is now a single source of truth for everything, which means it’s a single source of coupling. Change one slice, and you need to check if it breaks three other features. Testing state-dependent components requires mocking half the store.
Folder Structure Becomes Meaningless
You organized by type: components/, utils/, hooks/, services/. This works for discovery. But it doesn’t tell you what’s related. A feature might be spread across five folders. Deleting a feature means grepping the codebase to find all its pieces.
Dependencies Get Circular
Component A imports a util from Component B’s folder. Component B imports a hook that uses something from the store that was defined next to Component A. The dependency graph becomes a web instead of a tree. Build tools might not catch it immediately, but cyclic dependencies make refactoring risky.
Signs Your Architecture Is Degrading
Before fixing it, you need to see the problem clearly.
Changing one thing breaks something unrelated. You modify a component and a test in a completely different feature fails. This signals tight coupling or unclear boundaries.
New features take longer to build. Not because they’re complex, but because you spend hours finding where state lives, which component owns which logic, and whether you can modify this without breaking that.
Onboarding new developers takes weeks. They ask “where does X live?” and the answer is “well, it’s kind of everywhere.” You end up giving them a tour instead of pointing them to a clear folder.
Tests are fragile. They break when you refactor internals, not just when you change behavior. This usually means tests are too tightly coupled to implementation.
Refactoring feels risky. Even small improvements require careful manual testing because implicit dependencies aren’t visible.
How Complexity Creeps In
The key insight: it doesn’t happen all at once. It’s a thousand small decisions, each one reasonable at the time.
Developer A adds a useGlobalState hook for convenience. Fine.
Developer B needs data that’s already in the store, so imports it directly instead of passing it. Reasonable—the data’s already computed.
Developer C sees two similar components, decides not to merge them because the copy is “simpler” than refactoring. Understandable—refactoring is risky.
Each decision makes sense individually. Together, they create a system where everything depends on everything else.
Practical Steps to Fix It
1. Map the Current State
Before you fix it, understand what you have. Spend a day—not weeks—documenting:
- What state lives where?
- Which components depend on which pieces of state?
- What utilities are used by the most components?
- Which features are tightly clustered?
You don’t need a fancy visualization. Pen and paper, or a simple spreadsheet. The goal is to see the current reality.
2. Define Boundaries
This is the hard part, but it’s where the real fix happens.
Decide: what is a feature? What components belong together? What state is truly global vs. feature-specific?
A feature is a cohesive unit of functionality that makes sense together. Don’t split by component type; split by business domain. An “Authentication” feature includes login, logout, signup, and their associated state management.
Example folder structure (after):
src/
app/
features/
auth/
components/
login-form/
login-form.component.ts
signup-form/
signup-form.component.ts
store/
auth.reducer.ts
auth.actions.ts
services/
auth.service.ts
auth.module.ts
public-api.ts # explicit exports
dashboard/
components/
dashboard-layout/
dashboard-layout.component.ts
dashboard-card/
dashboard-card.component.ts
store/
dashboard.reducer.ts
services/
dashboard.service.ts
dashboard.module.ts
shared/
components/
button/
button.component.ts
modal/
modal.component.ts
services/
http.service.ts
utils/
format.ts
The key: each feature folder is mostly self-contained. If you need to delete dashboard/, you delete one folder.
3. Untangle State
Move state as close to where it’s used as possible.
Global state should hold only data that’s truly global: current user, auth status, theme. Feature-specific state stays in the feature folder. Local component state stays in the component.
// ❌ Global app.reducer.ts (too much)
export const initialState = {
currentUser,
tempFilters, // only used in ProductList
sortOrder, // only used in ProductList
searchQuery, // only used in SearchForm
notificationQueue, // only used in NotificationCenter
};
// ✅ Better: app.reducer.ts (only global)
export const initialState = {
currentUser,
theme: 'light',
};
// Feature-specific state stays in feature:
// features/products/store/products.reducer.ts
export const initialState = {
filters: {},
sortOrder: 'asc',
searchQuery: '',
};
This massive—your store shrinks from 50 slices to 5. Each feature manages its own state. Testing becomes simpler because fewer dependencies.
4. Create an Entry Point for Each Feature
Add a public-api.ts at the feature root that explicitly exports what’s public:
// src/app/features/auth/public-api.ts
export { AuthService } from './services/auth.service';
export { LoginFormComponent } from './components/login-form/login-form.component';
export { AuthModule } from './auth.module';
export type { AuthState } from './store/auth.reducer';
// Other services/components stay private
// If someone needs authInternal or a private component, that's a smell
This makes it obvious what’s meant to be used by other features. If someone imports from src/features/auth/store/authSlice directly, that’s a coupling smell you can catch in review.
5. Establish Dependency Rules
Enforce these rules:
- Features can depend on
shared/, but not on each other (except through defined public APIs). - Components can depend on hooks, utilities, types in their feature.
- Hooks can depend on services and store, but not vice versa.
- No circular dependencies.
This is easier to enforce with a tool like ESLint’s import/no-restricted-paths. In Angular, you can also use path aliases in tsconfig.json to make cross-feature imports obvious (e.g., @auth/public-api vs private imports). But even without tooling, making the rules explicit helps during review.
What to Change First
Don’t refactor everything at once. Start small.
Pick one feature that feels tangled. Spend a sprint:
- Moving its state into its folder
- Making its dependencies explicit with an
index.ts - Removing circular dependencies
Get it right. Other features will follow the pattern.
Then, migrate one feature at a time. As you move things, you’ll find opportunities to simplify the global state and utilities.
The Real Issue
The core problem isn’t technical—it’s about ownership and intention. A clean codebase requires someone enforcing boundaries. Not as a bottleneck, but as a design principle being upheld.
Your tech lead or most senior engineer should own structure. They don’t review every line, but they do:
- Review new files for placement
- Push back on cross-feature imports
- Propose refactorings when boundaries blur
- Document the structure
Without this, entropy wins. Code naturally degrades toward maximum coupling, maximum state sharing, and folders that mean nothing.
Conclusion
Frontend projects become messy because mental models don’t scale. A structure that works for five developers breaks for ten. A state design that’s fine at 2,000 lines becomes a nightmare at 20,000.
The fix isn’t a framework or tool. It’s intentionality. Define boundaries. Enforce them. Make coupling visible. Move state as close to where it’s used as possible.
Start now, before it’s too late. A day of refactoring at 5,000 lines saves months of frustration at 50,000.