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Understanding Modules

Angular is a platform that empowers developers to build applications for the web, mobile, and desktop. At the heart of Angular are its modules, which play a crucial role in structuring your Angular application. In this article, we'll dive deep into the concept of modules in Angular. This is not just a beginner's guide, but also a comprehensive article that covers all aspects of Angular modules.

What are Modules in Angular?​

In Angular, a module is a mechanism to group components, directives, pipes and services that are related, in such a way that they can be combined with other modules to create an application. An Angular application is a set of modules. Hence, modules in Angular help to organize an application into cohesive blocks of functionality.

Angular's Root Module​

Each Angular application has at least one module, known as the root module. By convention, the root module class is named AppModule and it resides in a file named app.module.ts. The root module is used to bootstrap the application. It is the starting point of your Angular application.

Here's a simple example of a root module:

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 { }

The @NgModule Decorator​

Angular modules are identified by decorated classes with @NgModule. The @NgModule decorator is a function that takes a single metadata object, whose properties describe the module. The most important properties are:

  • declarations: The components, directives, and pipes that belong to this NgModule.
  • exports: The subset of declarations that should be visible and usable in the component templates of other NgModules.
  • imports: Other modules whose exported classes are needed by component templates declared in this NgModule.
  • providers: Creators of services that this NgModule contributes to the global collection of services; they become accessible in all parts of the app.
  • bootstrap: The main application view, called the root component, which hosts all other app views. Only the root NgModule should set the bootstrap property.

Feature Modules​

Feature modules are Angular modules that group together related code. Each feature module encapsulates a specific application feature, complete with components, services, and related code files. Dividing your code into feature modules can help you organize your code and make it more maintainable.

Shared Modules​

Shared modules allow you to organize your code in such a way that commonly used components, directives, and pipes can be used across your entire application. This helps in reusing code across your application and keeps your code DRY (Don't Repeat Yourself).

Conclusion​

Modules in Angular are a great way to organize your code and separate concerns within your application. They are a fundamental aspect of any Angular application and understanding them is pivotal for an Angular developer. We have covered the basics of Angular modules in this article. As you continue your Angular journey, you'll learn even more about modules and how they can help you create clean, maintainable code.