A well-organized Angular project structure is crucial for maintaining the scalability, maintainability, and efficient development of the Angular app you want to bring to life.
Plus, keep in mind that there’s no one-size-fits-all approach, considering that finding the best suitable architecture for every project and use case is almost impossible. But lucky for us, choosing a structure that supports growth and flexibility isn’t.
In this guide, we’ll show you Angular project structure best practices, helping you create a solid, scalable, and maintainable architecture for your application so you can stay organized and understand where everything is. Whether it’s angular vs angular js, building a good project from scratch, or revamping a legacy application is easier when you follow angular best practices.
Angular Project Structure: An Overview
Building a scalable and maintainable Angular application starts with a good Angular framework. A great Angular project structure is a mix of a lot of different things: code reusability, simplified debugging, organized folders and easy navigation.
Now, before we get to the Angular project structure best practices, you first need to understand the different components that we will use to make up a good Angular structure.
Key Files and Directories in an Angular Project
While Angular doesn’t enforce a specific file organization, adopting a structured approach helps streamline development. Here’s a commonly used Angular folder structure:
/angular-project │── src/ │ ├── app/ │ │ ├── core/ # Singleton services (e.g., authentication, logging) │ │ ├── features/ # Feature modules (e.g., dashboard, user management) │ │ ├── shared/ # Reusable components, directives, and pipes │ │ ├── assets/ # Static assets (e.g., images, styles) │ │ ├── environments/ # Config files for different environments │ │ ├── main.ts # Entry point of the Angular app │ │ ├── app.module.ts # Root module that bootstraps the app │ ├── index.html # Main HTML file │ ├── styles.css # Global styles │── angular.json # Angular configuration file │── package.json # Dependencies and scripts │── tsconfig.json # TypeScript configuration │── README.md # Project documentation
Before we get ahead of ourselves, let’s read on to understand the overall Angular project structure. It generally contains workspace configuration files, application project files, and source files, making the angular folder structure easier to navigate. Here’s a detailed look into Angular file structure and what each file does:
- .vscode/ – This folder is created when you open the project in Visual Studio Code. It stores workspace settings specific to your project.
- node_modules/ – Contains all the npm packages your project depends on. If you ever need to check installed dependencies, you’ll find them here.
- src/ – The heart of your project. This folder holds all the application’s source code.
- .editorconfig – Defines coding style preferences to ensure consistency across different code editors.
- .gitignore – Lists files and folders that Git should ignore, keeping your repository clean.
- angular.json – The main configuration file for your Angular app. It defines project settings, build options, and more.
- package-lock.json – Automatically generated to lock dependency versions, ensuring consistency across installations.
- package.json – The project’s metadata file. It includes essential details like the project name, version, dependencies, and scripts.
- README.md – A Markdown file where you document your project, providing an overview, setup instructions, and usage guidelines.
- tsconfig.app.json – An extra TypeScript config file that lets you fine-tune TypeScript settings specifically for your application. Useful when working with multiple apps in an Angular workspace.
- tsconfig.json – The global TypeScript configuration file. If your project has multiple Angular subprojects, each will have its tsconfig.app.json while sharing this main config.
- tsconfig.spec.json – Configures TypeScript for test files, ensuring your unit tests run smoothly.
These files might seem like a handful, but they’re easier to handle when we use Angular project structure best practices. That being said, we can bundle the code into different folders—four categories to be exact:
Core Folder
The core/ folder contains services and utilities that should be available application-wide. Examples include authentication, API handling, and logging.
Features Folder
The features/ folder is where your app’s functionality is supposed to be. Each feature should have its module to ensure modularity.
For example, here’s a look at how the Dashboard module should be categorized in the Features Folder:
features/ ├── dashboard/ │ ├── dashboard.component.ts │ ├── dashboard.module.ts │ ├── dashboard.service.ts
Shared Folder
Reusable UI components, directives, and pipes should be placed in your Shared Folder. Also, remember to avoid adding services to this folder to prevent unintentional singleton behavior. If a service is provided in SharedModule, each Feature Module that imports SharedModule gets a new instance of the service. So, if your service is supposed to be singleton and you place it here, this can lead to data inconsistencies (for example, if you store user authentication state in the service, different parts of the app might not see the same user).
Assets and Environments
- assets/ holds static files (images, fonts, etc.).
- environments/ contains separate configurations for development, testing, and production.
Every Angular project consists of both configuration files and organized folders that make the app modular and scalable. It’s up to you to use Angular best practices to find the right Angular project structure for your app, to bundle away those stacks of code into readable and easy-to-find places—and speaking of Angular best practices, here are those you should keep in mind for better Angular structure:
Angular Project Structure Best Practices
While you are at it, you must know the Angular project structure best practices to ensure it remains thorough and direct.
1. Follow Feature-Based Module Organization
Instead of grouping by file type (e.g., components, services, models), use feature-based modules to encapsulate functionality.
Here’s an example of good feature-based structure:
/features/ ├── auth/ │ ├── auth.component.ts │ ├── auth.service.ts │ ├── auth.module.ts ├── products/ │ ├── product.component.ts │ ├── product.service.ts │ ├── product.module.ts ├── users/
Here, everything related to authentication (component, service, model, module) is inside one feature folder. So each feature module has its own components, services, and logic which makes your project more modular, scalable, and easier to maintain.
Compare that to this example of file-type-based organization, which isn’t a good practice:
/components/ ├── auth.component.ts ├── product.component.ts ├── user.component.ts /services/ ├── auth.service.ts ├── product.service.ts ├── user.service.ts /models/ ├── auth.model.ts ├── product.model.ts ├── user.model.ts /modules/ ├── auth.module.ts ├── product.module.ts ├── user.module.ts
In this structure, files are split by type, making it harder to manage. If you want to work on authentication, you will have to look in a bunch of different folders because of the difficult navigation in place. It’s difficult to track which services are being used in which modules.
2. Use Lazy Loading for Better Performance
Another of the Angular project structure best practices is using lazy loading. It’s essentially a strategy that ensures feature modules are loaded only when they’re needed, rather than loading everything up at the initial load of the application. This speeds up the initial loading time by a mile and improves performance.
To do this, you need to divide your app into feature modules and use lazy loading to improve performance by loading modules only when needed. Lazy loading is implemented using the loadChildren property in the Angular Router Module.
Here’s an example of what that may look like:
const routes: Routes = [
{ path: 'dashboard', loadChildren: () => import('./features/dashboard/dashboard.module').then(m => m.DashboardModule) },
{ path: 'products', loadChildren: () => import('./features/products/products.module').then(m => m.ProductsModule) },
{ path: 'users', loadChildren: () => import('./features/users/users.module').then(m => m.UsersModule) }
];
This reduces the amount of unnecessary JavaScript loaded upfront, as each path is created for a certain feature module (in this example, we have ‘dashboard’, ‘products’ and ‘users’). Notice that in each pathway, the specific module is not loaded at the start, it’s only loaded when the user navigates to that feature. This improves scalability since apps don’t slow down as more features are added, so the sky’s the limit.
However, there are certain instances where eager loading might be needed instead. For example, if the feature is critical for app startup, like authentication, then eager loading would be necessary for your angular framework.
3. Keep Services Singleton in Core Module
Services that should be shared across the application should be placed in the core/ module and provided at the root level. That’s because services (like authentication, logging, and API handling) should have only one instance across the entire application.
Let’s take the singleton service Authentication as our example. If you declare a service inside a feature module (AuthModule), multiple instances of the service may be created whenever the module is loaded. So if AuthModule is lazy-loaded, Angular will create a new instance of AuthService every time that module is loaded. This leads to inconsistent state, paving the way for unpredictable behaviors in your app. To fix this, follow Angular project structure best practices by placing shared services in the core folder and using providedIn: ‘root’.
Here’s an example of how it can help improve your angular structure:
@Injectable({ providedIn: 'root' }) // This ensures only ONE instance of AuthService
export class AuthService {
user: User | null = null;
login(email: string) {
this.user = { email };
}
getUser() {
return this.user;
}
}
Now, wherever AuthService is used in your app, it refers to that same instance, preventing inconsistent state and making sure your app doesn’t ‘forget’ that the user is logged in.
4. Separate UI Components and Business Logic
In a good Angular project structure, the components should focus on displaying data (UI logic), while the services should handle the business logic (data fetching, API calls, authentication, etc.). This follows the Separation of Concerns (SoC) principle, making code more maintainable for you and easier in the long run if you plan to hire angular developers.
To follow Angular project structure best practices, you should move API calls and business logic to a separate service inside the core folder or feature folder. Let’s get into the details of this with an example:
// User Service (Handles API Calls) - Place in core or feature module
@Injectable({ providedIn: 'root' })
export class UserService {
constructor(private http: HttpClient) {}
getUser(userId: number) {
return this.http.get(`https://api.example.com/user/${userId}`);
}
}
// User Component (Only Handles UI Logic)
export class UserComponent {
user: any;
constructor(private userService: UserService) {}
ngOnInit() {
this.userService.getUser(1)
.subscribe(data => this.user = data);
}
}
Following this leads to better angular folder structure since API calls can then be used in multiple components and unit testing services separately is also now simpler.
5. Use TypeScript Interfaces for Data Models
In a structured Angular project, instead of using plain objects to store and manage data, you should define TypeScript interfaces for your data models. This improves code readability, type safety, and maintainability.
If you handle data as plain Javascript objects, the code can’t warn you if an expected property is missing or misused. Plus, it’s harder to maintain because it’s unclear what data fields exist without inspecting the API responses.
Instead, define an interface inside the shared folder and use it wherever that data model is needed.
Here’s an example:
// Define a User Interface (Place in shared/models/user.model.ts)
export interface User {
id: number;
name: string;
email: string;
}
What this does is that the Interfaces define a clear data structure for all parts of the app and the Type safety ensures errors are caught at compile time, not runtime. They also improve the developer experience by enabling auto-completion and hints in IDEs, making code easier to read and work with.
6. Organize Testing Files
Some developers create a separate tests/ folder to store all test files, but this violates Angular project structure best practices because then tests go into state of disconnection from the code that needs to validate. Those developers then have to switch between folders to find test files they’re looking for and as the project grows, the tests/ folder becomes cluttered, leaving absolutely no room for scalability.
In a well-structured Angular project, the test files should be placed alongside the files they are testing rather than being grouped into a separate tests/ folder. This keeps the Angular folder structure clean, improves code maintainability, and makes it easier to find and update tests when modifying any features in the future.
So place .spec.ts files in the same directory as the tested files for easy maintenance. Here’s how:
/angular-project │── src/ │ ├── app/ │ │ ├── features/ │ │ │ ├── dashboard/ │ │ │ │ ├── dashboard.component.ts │ │ │ │ ├── dashboard.component.spec.ts // Reduces file clutter… │ │ │ │ ├── dashboard.service.ts │ │ │ │ ├── dashboard.service.spec.ts //And easier to find, too
Restructure an Angular Project: Step-by-Step Guide
If your project is already set up but lacks structure, it might not be performing at its best. You might be facing issues like slow loading times, having difficulty navigating through heaps of code, and of course maintaining your Angular project might be a hassle. Here are a few ways that you can restructure your angular project and get it back on track:
1. Identify the Structure and the Core and Feature Modules
Before you begin, there must be some difficult areas that need improvement, which you’re already aware of. Identify any patterns of disorganization, code duplication, or poor component separation.
Then it’s time to start restructuring your Angular project. Following angular best practices, identify which parts of your application belong in which module. Move the singleton services and shared services to the core/ module and the UI components to the features/ module.
2. Refactor Code into Separate Modules
The next step to better angular structure is to break monolithic files into smaller, manageable feature-based modules.
To improve organization and maintainability, refactor your Angular project by moving the global services (e.g., AuthService, LoggerService) to the core/ module, ensuring that there’s a single instance across the app.
Organize all the features into separate modules, keeping related components and services self-contained in the features/ folder. Place the reusable UI components, directives, and pipes in the shared/ module to prevent duplication.
Finally, update module imports in app.module.ts and feature modules. This restructuring reduces the complexity, enhances modularity, and sets the stage for better performance—meaning now you can apply the design strategy of lazy loading, making your app faster and easier to maintain.
3. Implement Lazy Loading
After all the pieces of your Angular project structure are in place like a puzzle, it’s time to adjust the routing to implement lazy loading by ensuring feature modules load only when needed.
First, remove the direct imports of feature modules in app.module.ts, then update app-routing.module.ts to use the loadChildren property for dynamic loading. Each feature module should define its own routing inside a feature-routing.module.ts file.
Finally, verify that your lazy loading works by checking the network tab in the browser’s dev tools.
4. Enforce Separation of Concerns
To keep your Angular project structure clean and maintainable, separate UI components from business logic.
A common issue in Angular projects is placing too much logic inside the components, making them difficult to test and reuse. To fix this, just extract business logic, API calls, and data transformations into services. Components should focus only on handling user interactions and displaying data.
This separation improves readability, maintainability, and makes unit testing easier, leading to a more modular and scalable project for the future.
5. Use Consistent Naming Conventions
Then it’s time to re-organize your angular structure by using consistent naming conventions across the components, services, and modules for better readability and scalability.
Follow Angular’s recommended naming patterns, such as using dash-case for file names (user-profile.component.ts) and PascalCase for class names (UserProfileComponent).
Also, ensure that service files are named with .service.ts, modules with .module.ts, and routing files with .routing.module.ts. In the long run, you won’t face any problem when dealing with bigger and more complex datasets.
6. Update Imports and Dependencies
The next step would be double-checking to make sure all the paths reflect the new structure.
After restructuring your folders and modules, update all import paths to reflect the new structure. Check for outdated or unnecessary dependencies in package.json, and clean up any redundant imports in your files.
Use TypeScript path aliases in tsconfig.json to simplify long or complex import statements. It might seem tedious, but properly managing imports and dependencies reduces errors and keeps your Angular project organized.
7. Run Tests to Validate Changes
Last but not least, we now have to check for broken imports and ensure functionality remains intact.
Once the restructuring is complete, run all tests to verify that nothing is broken. Unit tests (.spec.ts files) should be executed to ensure individual components and services work correctly.
Also, perform end-to-end (E2E) tests to check the overall functionality of your Angular framework. Fix any broken imports, missing dependencies, or failing test cases. Thorough testing ensures that all the hard work you’ve put in to restructure your Angular project doesn’t go to waste and you get a stable and fully functional app.
Conclusion
Following a structured Angular folder structure is crucial for building maintainable applications. By implementing Angular project structure best practices, including feature-based organization, lazy loading, and separation of concerns, you can ensure your app remains scalable and easy to maintain.
Or, if your time and expertise fall short, you can simply hire Angular developers to help build and maintain your Angular project and ensure that the first step you take is in the right direction.
Frequently Asked Questions
What are the key files and folders in an Angular project?
A structured Angular project consists of essential files and folders that organize the code efficiently. The main folders include src/, app/, core/ folder, features/ folder, shared/ folder, and the assets/ folder. Key files include angular.json, package.json, tsconfig.json, and README.md.
Why is a good Angular project structure important?
A well-organized Angular project improves the development efficiency by making the code easier to maintain and navigate, allowing multiple developers to work on different modules without conflicts. It also boosts performance and promotes reusability, all while remaining scalable so your app can reach new heights without hassle.
What is the purpose of the angular.json file?
The angular.json file is the central configuration file for any Angular project. It defines build settings and manages assets and global styles, ensuring that there’s consistent design across the entire project.
What is the difference between feature, core, and shared modules?
In an Angular project structure, modules help organize the code efficiently. Feature modules, located in the features/ folder, hold distinct functionalities like dashboards, users, or products, making them easier to manage and load independently. The Core module, found in the core/ folder, contains the singleton services such as authentication and logging, ensuring these services are available throughout the app without duplication. The Shared module, stored in the shared/ folder, holds the reusable UI components, directives, and pipes that can be used across different modules.
How does lazy loading improve an Angular project?
Lazy loading enhances an Angular project’s performance by ensuring that only necessary modules are loading initially. It reduces the initial bundle size and also optimizes resource usage by preventing unnecessary code from loading into memory.
