Best Practices for Angular App Development: Folder Structure, Naming, Lazy Loading, and More!

Angular is a popular web framework for building complex and large-scale applications. It provides a wide range of features to developers to build efficient and maintainable applications. When developing an Angular application, having a well-structured project can help to organize the codebase and make it easier to maintain and extend in the future. Here are some best practices for structuring an Angular project:

Divide the code into modules

Dividing code into modules is an important part of Angular application development as it helps to organize the code and makes it more reusable. Here is an example of how you can divide code into modules:

Suppose you have a feature in your application called "User Management", which includes functionality for creating, reading, updating, and deleting user records. To organize this feature, you can create a user-management module.

Create a new file called `user-management.module.ts` in a folder named user-management within the modules folder of your project.

typescript

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';

import { UserListComponent } from './user-list/user-list.component';
import { UserDetailComponent } from './user-detail/user-detail.component';
import { UserService } from './user.service';

@NgModule({
  declarations: [
    UserListComponent,
    UserDetailComponent
  ],
  imports: [
    CommonModule,
    FormsModule,
    ReactiveFormsModule
  ],
  providers: [
    UserService
  ]
})
export class UserManagementModule { }

In the `user-management.module.ts` file, import the necessary Angular modules for your feature, such as `CommonModule`, `FormsModule`, and `ReactiveFormsModule`. Then, declare any components that are specific to the feature, such as `UserListComponent` and `UserDetailComponent`. Finally, include any services that are used within the feature, such as `UserService`.

In each of the component files, import the necessary modules and services for that component.

typescript

import { Component } from '@angular/core';
import { UserService } from '../user.service';

@Component({
  selector: 'app-user-list',
  templateUrl: './user-list.component.html'
})
export class UserListComponent {
  users: User[];

  constructor(private userService: UserService) {}

  ngOnInit() {
    this.userService.getUsers().subscribe(users => {
      this.users = users;
    });
  }
}

In the `UserListComponent`, we have imported the `UserService` which is provided by the `UserManagementModule`.

Finally, add the `UserManagementModule` to the imports array of the app module (`app.module.ts`) so that it is available throughout the application. If you don't want it to be available in the whole application, and you want to lazy load that code you can link it through the app-routing module. The concept of lazy loading is described in a later chapter of this article.

typescript

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { UserManagementModule } from './modules/user-management/user-management.module';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    UserManagementModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

This will allow us to use the components and services defined in the `UserManagementModule` throughout our application. By dividing our code into modules, we can keep our code organized, reusable, and easier to maintain.

Use a consistent naming convention

Using a consistent naming convention is an important aspect of writing maintainable and easy-to-read code. In Angular, it is common to use a variation of the "CamelCase" convention for naming variables, functions, classes, and other code elements.

Here is an example of how to use a consistent naming convention in an Angular component:

typescript

import { Component, OnInit } from '@angular/core';
import { UserService } from '../services/user.service';
import { User } from '../models/user.model';

@Component({
  selector: 'app-user-list',
  templateUrl: './user-list.component.html',
  styleUrls: ['./user-list.component.scss']
})
export class UserListComponent implements OnInit {
  users: User[];

  constructor(private userService: UserService) {}

  ngOnInit(): void {
    this.userService.getUsers().subscribe(users => {
      this.users = users;
    });
  }

  deleteUser(user: User): void {
    this.userService.deleteUser(user.id).subscribe(() => {
      this.users = this.users.filter(u => u.id !== user.id);
    });
  }
}

In this example, we can see that the class name (`UserListComponent`) and the file name (`user-list.component.ts`) both follow the "CamelCase" convention, where the first letter of each word is capitalized. We also use the suffix "Component" to indicate that this is an Angular component.

The selector (`app-user-list`) also follows a consistent naming convention, using a prefix of "app-" followed by the component name in "kebab-case" (where words are separated by hyphens).

The variable name for the `UserService` is also consistent with the naming convention, where we use the name of the service in "camelCase" and prefix it with a lowercase letter to indicate that it is a private variable.

Similarly, the method names (`ngOnInit()` and `deleteUser()`) and parameter names (`user`) both follow the "camelCase" convention.

By using a consistent naming convention throughout our code, we can make our code more readable and easier to maintain.

Use lazy loading

Lazy loading is a technique used in Angular to improve application performance by loading modules on demand instead of all at once during the initial application load. This can significantly reduce the initial load time of an application, as well as decrease the amount of memory required to run the application.

Here is an example of how to use lazy loading in an Angular application:

Suppose you have a feature in your application called "User Management", which includes functionality for creating, reading, updating, and deleting user records. To lazy load this feature, you can create a user-management module and configure the routing to load it lazily.

Create a new file called user-management.module.ts in a folder named user-management within the modules folder of your project.

typescript

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';

import { UserListComponent } from './user-list/user-list.component';
import { UserDetailComponent } from './user-detail/user-detail.component';
import { UserService } from './user.service';
import { RouterModule, Routes } from '@angular/router';

const routes: Routes = [
  {
    path: '',
    component: UserListComponent
  },
  {
    path: ':id',
    component: UserDetailComponent
  }
];

@NgModule({
  declarations: [
    UserListComponent,
    UserDetailComponent
  ],
  imports: [
    CommonModule,
    FormsModule,
    ReactiveFormsModule,
    RouterModule.forChild(routes)
  ],
  providers: [
    UserService
  ]
})
export class UserManagementModule { }

In the `user-management.module.ts` file, define the routes for your feature using the `RouterModule.forChild()` method. This will create a new child router for the `UserManagementModule`. Also, declare any components that are specific to the feature, such as `UserListComponent` and `UserDetailComponent`. Finally, include any services that are used within the feature, such as `UserService`.

Update the app routing module (`app-routing.module.ts`) to configure the lazy loading of the `UserManagementModule`.

typescript

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';

const routes: Routes = [
  {
    path: 'users',
    loadChildren: () => import('./modules/user-management/user-management.module').then(m => m.UserManagementModule)
  }
];

@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

In this example, we have updated the app routing module to configure the lazy loading of the `UserManagementModule`. When the user navigates to the `'/users'` URL, the module will be loaded lazily.

By using lazy loading, we can significantly improve the performance of our Angular application. The user will only load the modules they need, and not the ones they don't.

Separate concerns in Angular

Separation of concerns is a fundamental principle in software engineering that refers to the practice of breaking down a program into distinct components, each responsible for a single, well-defined function. The goal of this principle is to make code more modular, maintainable, and easier to understand.

In an Angular application, separation of concerns can be achieved by dividing the code into modules, components, services, and other Angular constructs that each have a specific responsibility. For example, a component may be responsible for rendering a specific view, a service may be responsible for fetching data from an API, and a module may be responsible for grouping together related components and services.

Here are a few examples of how separation of concerns can be achieved in an Angular application:

Components should be responsible for rendering views and handling user interactions, while services should be responsible for data access and business logic.

For example, suppose you have a `UserListComponent` that displays a list of users. Rather than including code in the component to fetch the list of users from an API, you can create a separate UserService that handles data access. The `UserListComponent` can then inject the `UserService` and call its methods to fetch and display the data.

Modules should be responsible for grouping related components and services, while also providing any necessary configuration and dependency injection.

For example, you may have a `DashboardModule` that includes components for displaying charts and graphs, as well as a `DashboardService` that provides data for those components. The `DashboardModule` can then be imported into the `AppModule` to provide those components and services to the rest of the application.

Directives should be responsible for manipulating the DOM or behavior of components in a declarative way.

For example, you may have a directive that adds a tooltip to a button when the user hovers over it. Rather than including code in the component to handle this behavior, you can create a separate TooltipDirective that applies the tooltip to any element that it is attached to.

By separating concerns in this way, we can make our Angular applications more modular, maintainable, and easier to understand. This makes it easier to develop new features, refactor existing code, and fix bugs.

Use a consistent folder structure

Grouping related code together can help to make it easier to navigate and understand. For example, create a folder for each feature or section of the application, and place all the related components, services, and directives in that folder.

Having a consistent folder structure can make it easier to find and navigate code. For example, place all components in a 'components' folder, all services in a 'services' folder, and so on. An example of a prefered folder structure could look like this:

Text

|-- app
|   |-- core
|   |   |-- guards
|   |   |-- interceptors
|   |   |-- models
|   |   |-- services
|   |   `-- core.module.ts
|   |-- shared
|   |   |-- components
|   |   |-- directives
|   |   |-- pipes
|   |   `-- shared.module.ts
|   |-- modules
|   |   |-- home
|   |   |   |-- components
|   |   |   |-- services
|   |   |   |-- home-routing.module.ts
|   |   |   `-- home.module.ts
|   |   |-- auth
|   |   |   |-- components
|   |   |   |-- services
|   |   |   |-- auth-routing.module.ts
|   |   |   `-- auth.module.ts
|   |   `-- dashboard
|   |       |-- components
|   |       |-- services
|   |       |-- dashboard-routing.module.ts
|   |       `-- dashboard.module.ts
|   `-- app.component.ts
|   `-- app.module.ts
|   `-- app-routing.module.ts
|-- assets
|   |-- images
|   |-- fonts
|   |-- styles
|   `-- config.json
|-- environments
|   |-- environment.prod.ts
|   `-- environment.ts
|-- index.html
|-- main.ts
|-- styles.scss
|-- package.json
|-- tsconfig.json
|-- tslint.json
|-- angular.json
|-- karma.config.js
`-- README.md

Here's a breakdown of each folder and its purpose:

`app` folder: This folder contains all the application-specific code.
- `core` folder: This folder contains the code that is shared across the entire application, such as services, models, guards, and interceptors. The `core.module.ts` file is responsible for importing and exporting these shared items.
- `shared` folder: This folder contains shared components, directives, and pipes that are used across the application. The `shared.module.ts` file is responsible for importing and exporting shared items, for instance `TranslateModule.forChild()`.
- `modules` folder: This folder contains the feature modules of the application. Each feature module is organized into its own folder, which contains all the components, services, and routing information for that feature. The naming convention for feature modules is typically [feature-name].module.ts.
`assets` folder: This folder contains static files used in the application, such as images, fonts, and stylesheets. The config.json file can also be stored here to hold any configuration data.
`environments folder`: This folder contains the environment-specific configuration files, such as environment.prod.ts and environment.ts. These files can hold environment-specific variables and settings.
`index.html`: This file is the main entry point of the application and includes the application's root component.
`main.ts`: This file is the entry point of the application and bootstraps the AppModule.
`styles.scss`: This file contains global styles for the application.
`package.json`: This file lists all the dependencies of the application.
`tsconfig.json`: This file specifies the TypeScript compiler options for the application.
`tslint.json`: This file specifies the TSLint configuration for the application.
`angular.json`: This file contains the

Use interfaces

In Angular, interfaces are a powerful tool for defining and enforcing contracts between different parts of an application. An interface is a way to define a custom data type that specifies the shape of an object, including its properties and their types. By using interfaces, we can ensure that components, services, and other parts of our application are working with data that meets our specific requirements.

Here are a few ways that interfaces can be used in an Angular application:

Define the shape of data returned from an API: When we receive data from an API, we need to make sure that the data has the correct shape and types. We can create an interface that describes the expected shape of the data and use it to enforce type safety. For example:

typescript

interface User {
  id: number;
  name: string;
  email: string;
}

@Injectable()
export class UserService {
  constructor(private http: HttpClient) {}

  getUsers(): Observable<User[]> {
    return this.http.get<User[]>('/api/users');
  }
}

Use a build tool

In the context of an Angular application, a build tool is a software tool that automates the process of compiling the TypeScript code into JavaScript, bundling the application code and assets into optimized files, and preparing the application for deployment. The most commonly used build tool for Angular applications is the Angular CLI (Command Line Interface).

Here are some reasons why using a build tool like the Angular CLI is important:

Automates repetitive tasks: A build tool automates the repetitive and time-consuming tasks of building and deploying an Angular application. For example, the Angular CLI can create a new project, generate new components, services, and modules, compile and bundle the code, and prepare the application for deployment with a single command.
Optimizes performance: A build tool optimizes the performance of an Angular application by bundling the code and assets into smaller and more efficient files. This reduces the download time and improves the overall performance of the application.
Enforces best practices: A build tool like the Angular CLI enforces best practices and conventions for developing and deploying Angular applications. For example, it automatically generates code that follows the recommended file structure, naming conventions, and coding style.
Simplifies deployment: A build tool simplifies the deployment of an Angular application by creating optimized and compressed files that can be easily deployed to a web server or cloud-based hosting platform.

Use version control

Version control is a software tool that allows developers to manage changes to the source code of an application over time. It tracks every modification made to the code and provides a historical record of all changes made to the codebase.

Using version control in software development has many benefits, including:

Collaboration: Version control enables developers to work collaboratively on the same codebase without overwriting each other's changes. It allows multiple developers to work on the same code simultaneously and merge their changes seamlessly.
Code backup and recovery: Version control creates a backup of the codebase, so developers can easily recover previous versions of the code if something goes wrong.
Code review: Version control provides an easy way to review code changes and identify errors or potential problems before the code is merged into the main codebase.
Experimentation: Version control enables developers to create and experiment with new features or ideas without affecting the main codebase. They can create a branch of the codebase to work on, test their changes, and merge them back into the main codebase if they are successful.
Traceability: Version control allows developers to track who made changes to the code and when, making it easier to identify the cause of bugs or issues.

In summary, version control is an essential tool for software development that allows developers to manage changes to the codebase, collaborate effectively, and ensure code quality and reliability.

Summary

In this article, we discussed several best practices for developing Angular applications, including:

Folder structure: Organize the code into modules, components, services, and other related files in a well-structured folder hierarchy.
Consistent naming convention: Use a consistent naming convention for files, components, services, and other parts of the application to make it easy to understand and navigate the codebase.
Lazy loading: Use lazy loading to load modules on-demand, improving the performance of the application and reducing the initial loading time.
Separation of concerns: Separate concerns and responsibilities of different parts of the application to make it easier to manage and maintain the code.
Interfaces: Use interfaces to define object types and improve the type safety of the code.
Build tool: Use a build tool like the Angular CLI to automate repetitive tasks, optimize the performance of the application, enforce best practices, and simplify the deployment process.

Additionally, we discussed the importance of version control in software development, which allows developers to manage changes to the source code of an application over time, collaborate effectively, and ensure code quality and reliability. By following these best practices and using version control, developers can create high-quality Angular applications that are easy to develop, maintain, and deploy.

Frontend

Backend

Other

Best Practices for Angular App Development: Folder Structure, Naming, Lazy Loading, and More!

Divide the code into modules

Use a consistent naming convention

Use lazy loading

Separate concerns in Angular

Components should be responsible for rendering views and handling user interactions, while services should be responsible for data access and business logic.

Modules should be responsible for grouping related components and services, while also providing any necessary configuration and dependency injection.

Directives should be responsible for manipulating the DOM or behavior of components in a declarative way.

Use a consistent folder structure

Use interfaces

Use a build tool

Use version control

Summary