Angular folder structure explanation & best practices
As for the src, node_modules folders, and angular.json files in the Angular folder structure, they can cause confusion. What should you do when you see them for the first time? Don't worry! The folder structure of Angular is designed to be intuitive and scalable, making large projects easier to manage.
In this blog post, we will explain the Angular folder structure step by step to give you a clear understanding of what each folder and file does, and the execution flow of an Angular application. After reading this article, you should have full knowledge so that, with confidence in your heart, you can also build future Angular applications accordingly, knowing they are following best practices.
Understanding Folder Structure at a Glance
Before we get into specific details about the folder structure itself, let me tell you why understanding it is so important:
- Organization: A well-organized project makes it easier to find and share files with teammates.
- Scalability: As your software grows, having a clear structure prevents adding new features from becoming hectic.
- Debugging: Knowing where everything is located helps you quickly resolve errors when they arise.
- Best Practices: Fly the flag for Angular with code that conforms to the highest industry standards!
First, let's examine the default folder structure generated by Angular CLI.
Angular Folder Structure Explained
The following folder structure is created when you generate a new Angular project using the Angular CLI (ng new my-app):
my-app/
├── e2e/ # End-to-end testing files
├── node_modules/ # Installed dependencies
├── src/ # Application source code
│ ├── app/ # Core application logic
│ │ ├── app.component.ts # Root component
│ │ ├── app.module.ts # Root module
│ │ └── ... # Other components, services, etc.
│ ├── assets/ # Static files (images, fonts, etc.)
│ ├── environments/ # Environment-specific configuration
│ ├── index.html # Main HTML file
│ ├── main.ts # Entry point of the application
│ ├── styles.css # Global styles
│ └── test.ts # Test entry point
├── .gitignore # Files ignored by Git
├── angular.json # Angular configuration file
├── package.json # Project dependencies and scripts
├── README.md # Project documentation
└── tsconfig.json # TypeScript configuration
1. Explanation of src/
The src folder is the core of your application, often called the heart of an Angular project where all the code resides.
- app/ : Contains the core logic of your app, including components, modules, services, and routing configurations.
- app.component.ts: The root component of your app. Every Angular app must have at least one component, and this is it.
- app.module.ts: The root module of your app. It describes all the components, directives, and pipes used in your app.
- assets/: Stores static files like images, icons, and JSON data.
- environments/: Holds environment-specific configuration files for development and production API endpoints.
- index.html: The primary file provided to browsers with all its content dynamically injected by Angular.
- main.ts: The start of your application. The entry point of your application.
- styles.css: Global styles used across the entire app.
2. node_modules/
This folder contains all third-party libraries, installed using npm, to save time and effort.
3. angular.json
This file contains configuration settings for your Angular project, such as build options, file paths, and environments.
4.package.json
This file lists all project dependencies, such as installation directories and scripts (e.g., npm start runs the start script).
5. tsconfig.json
This file provides the TypeScript configuration needed to compile JavaScript properly.
Angular Execution Flow: How Everything Works
Now that we have explained Angular’s folder structure, let’s delve into the execution flow of an Angular application. Here is a step-by-step rundown of what happens when you run ng serve:
Step 1: Booting the App
- The process starts in the main.ts file, the entry point.
- The platformBrowserDynamic().bootstrapModule(AppModule) function initializes the root module (AppModule) and starts the app.
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppModule } from './app/app.module';
platformBrowserDynamic().bootstrapModule(AppModule)
.catch(err => console.error(err));
Step 2: Loading the Root Module
- The AppModule is loaded. This module defines the application’s components, services, and other dependencies.
- The @NgModule decorator in app.module.ts specifies metadata like declarations, imports, providers, and the bootstrap component.
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
@NgModule({
declarations: [AppComponent],
imports: [BrowserModule],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule {}
Step 3: Rendering the Root Component
- The AppComponent (defined in app.component.ts) is rendered into the index.html file.
- Angular uses the <app-root> selector to inject the root component into the DOM.
<!-- index.html -->
<body>
<app-root></app-root>
</body>
Step 4: Handling User Actions
- Angular watches for events like clicks and keystrokes, dynamically updating the view using its change detection mechanism.
- Components interact with services to fetch data and perform operations.
Step 5: Building and Serving
- When you run
ng serve, Angular compiles your TypeScript code into JavaScript, bundles it, and serves it on a local development server (default:http://localhost:4200).
Best Practices for Managing Angular Projects
- Use Consistent Naming Conventions: Maintain consistency in naming components, services, and modules.
- Feature-Oriented Organization: Group related files within feature-specific folders.
- Keep app.module.ts Clean: Import only necessary modules and use feature modules.
- Lazy Loading: Load only required modules to improve performance.
- Use Angular CLI: Use
ng generatefor scaffolding components, services, and modules.
Understanding the Angular folder structure and execution flow is crucial for building scalable applications confidently. Follow best practices to maintain a well-structured project that is easy to manage and expand.