What Are the Main Building Blocks of an Angular Application?

Krunal Shah

Oct 13, 2022

6 min readLast Updated Nov 30, 2022

Angular application

Angular is a component-based framework that is suitable to deploy highly scalable web applications. Released in September, 2016, Angular has garnered wide popularity over the past decade due to several advantages of Angular such as cross-platform compatibility, high speed, enhanced performance, faster development and better code readability, to name a few. Let’s know the key building blocks required for an Angular application development.

The Key Building Blocks of an Angular Application

There are 8 building blocks of an Angular application as listed below -

1. Modules

There are two types of modules in Angular - root modules and feature modules.

Represented as NgModule, modules are dedicated to maintain the modularity of an Angular application. Here modularity refers to the ability of an application in terms of upgrading, modification, disassembling, removing/modifying parts, and others.

A module functions like a cohesive group of codes that offers a compact compilation context for diverse solutions, services, and parts. The root module, which is known as AppModule of an Angular app, helps in bootstrapping while NgModules help consolidate different types of directives, pipes, and components into the cohesive blocks with well-defined functionalities.

Below is an example of importing modules in Angular -

import { BrowserModule } from '@angular/platform-browser';

import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';

@NgModule({

declarations: [

AppComponent

],

imports: [ /* add modules for Angular to use as required */

BrowserModule,

],

providers: [],

bootstrap: [AppComponent]

})

export class AppModule { }

Modules are crucial for Angular as they function as a collection of JavaScript modules with their respective functionalities. Here’s some of the highly used modules and their respective functionalities in Angular -

Module Name

Functionality

HttpClient Module

Communicating with a server using the Http protocol

BrowserModule

Running applications on browser

FormsModule

Building template based forms

ReactiveFormsModule

Building Reactive forms

CommonModule

Implementing NgIf and Ngfor

Angular application

2. Components

Components are the main building blocks for the UI designing in Angular that lets you easily style through various CSS styling and other relevant components suitable for the specific devices.

The components in Angular generally have different types of file formats such as .css, .js, and .html files which are focused on styling, interactivity, and structuring respectively. Below is an example of creating a component named ‘code-bucket.’

Import { Component } from ‘@angular/core’;

@Component {{

selector: ‘code-bucket’,

template: ‘<h1>building a code bucket.</h1>’,

styles: [‘h1 { font-family: Lato; color:pink; }’]

}}

Export class CodeBucketComponent {

}

An Angular app is built with a set of Angular components that are subsets of Angular directives and relevant to a specific template. There are mainly two types of components in Angular -

Parent Component - A parent component in Angular refers to a predefined and imported component in Angular that you can use as per your requirements.

Child Component - Unlike the parent components, a child component can be created and defined as and when needed.

There are mainly three types of configuration options for the components in Angular that are widely utilized by the developers -

Selector - The Selector configuration helps define how and where to deploy and insert the instance of this component.

Template URL - A Template URL is dedicated to define the view of the component host.

Providers - Providers in Angular are generally displayed in the form of arrays and help define and implement the interface of the providers.

See More: Angular 14: All the Important Features and Updates

3. Templates

Templates are a collection of HTML in Angular that helps in rendering in several areas such as the user interface, overall view, browsers, and others while facilitating specific functionalities.

Not only do templates help in organizing the views hierarchically, but they also let you easily change, modify, show, or hide various UI sections or pages as a unit. A template defines the host view of its related component. While the display of a page can be defined by template internally, for external display templateurl is used.

4. Metadata

Metadata in Angular defines a class to ensure that it executes the functions it is intended to. Metadata is crucial in configuring a class to exhibit its intended properties and hence is considered to be one of the prime building blocks during Angular development.

@Component ({

selector: ‘code-bucket’

templateurl:  ‘./code-bucket.component.html’,

Styles: [‘h1 { font-family: Lato; color:pink; }’]

})


Some of the key components of metadata include -

  • Selector: A selector refers to the CSS element that is focused to represent a specific component.
  • TemplateURL: The function of a template URL is as discussed above.
  • StyleURL: The core function of styleURL is similar to the TemplateURL except the fact that TemplateURL can be only one while there can be multiple StyleURLs for multiple CSS files.
Angular application

5. Data Binding

Data binding in Angular is pivotal to streamline and define the communication between a Document Object Model (DOM) and a specific component.

Below is an example of data binding in Angular -

<p>One way binding: </p>

<h1>{{ sentence }}</h1>

<p>Property binding:

<input [value]=”sentence” />

</p>

<p>Attribute binding:

<button [attr.aria-label]=”OK”>YES!</button>

</p>

There are mainly five types of data binding -

One Way Data Binding: It is defined as the data binding from a specific component to the DOM, such as HTML.

Property Data Binding: It refers to the data binding for a data variable of a component where the binding is done with the specific property so that a notification is sent for any possible change in the property.

Attribute Binding: It refers to the binding between an element and its attribute.

Two Way Binding: In two way binding, any changes in one side affects the other side.

Event Binding: This type of binding is applicable to the events created by the users and this type of binding takes place from a DOM to a component.

See More: Angular Elements

6. Directives

A directive in Angular is defined as a .js/.ts class that is declared with Directive to enable you to change or modify the UI elements during the runtime.

Below is an example of building a directive called NewDirective -

Import { Directive, ElementRef } from ‘@angular/core’;

@Directive ( {

selector: ‘ [NewHighlight] ‘

})

export class HighlightDirective {

constructor (el: ElementRef) {

el.nativeElement.style.backgroundColor = ‘red’;

}

}

There are mainly three types of directives in Angular -

Component Directives: Component directives include the details related to the process flow of a component,its  usage and other relevant information.

Attribute Directives: Attribute directives are focused on modifying, changing, or updating the behavior of the DOM elements.

Structural Directives: Structural directives are meant to configure and manipulate diverse DOM elements.

7. Services

Services in Angular are represented as Injectable. They are basically the classes that let you use data in various components as per your requirements. This simplifies your tasks of writing request codes every time you have requirements to use various methods.

Also, it reduces the risks of code duplication. All you need to do is deploy a data service that is injectable and caters to your requirements. Below is an example of using services in Angular -

Import { Injectable, EventEmitter } from ‘@angular/core’;

@Injectable()

export  class TasksService {

8. Dependency Injection

Dependency injection refers to the process of injecting a service into the constructor of a component. Not only does it help improve the reusability of a code, but makes the codes even more efficient and modular. Below is an example of dependency injection in Angular -

@Injectable()

class AppSolution {}

@Component({

selector: 'app-list',

template: '...',

providers: [AppSolution]

})

class AppListComponent {}

@NgModule({

declarations: [AppListComponent]

providers: [AppSolution]

})

class AppListModule {}

@Injectable({

providedIn: 'root'

})

class AppSolution {}


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