Angular is a platform and framework for building single-page client applications using HTML and TypeScript. It provides a rich set of tools and features that enhance developer productivity and application performance.

• Modules: The building blocks of an Angular application.
• Components: The fundamental UI building blocks.
• Templates: Define the UI layout and structure.
• Services: Used for business logic and data retrieval.
• Dependency Injection: A design pattern for managing dependencies.
• Routing: Navigating between different views or components.

Modules are a way to group related code. Every Angular application has at least one module, the root module, which is bootstrapped to launch the application.

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 { }
            

Components are the basic building blocks of an Angular application. Each component consists of an HTML template, a TypeScript class, and CSS styles.

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

@Component({
  selector: 'app-hello-world',
  template: '
Hello, Angular!
',
  styles: ['h1 { color: blue; }']
})
export class HelloWorldComponent { }
            

Services are used to encapsulate business logic and are typically injected into components via Angular's dependency injection system.

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

@Injectable({
  providedIn: 'root', // Makes the service available application-wide
})
export class DataService {
  getData() {
    return ['Data 1', 'Data 2', 'Data 3'];
  }
}
            

Dependency Injection (DI) is a software design pattern that allows a class to receive its dependencies from external sources rather than creating them itself.

Angular uses a hierarchical dependency injection system, allowing services to be provided at different levels of the application.

Routing in Angular allows navigation from one view to another as users perform tasks in the application. The RouterModule facilitates the routing functionality.

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { HomeComponent } from './home/home.component';
import { AboutComponent } from './about/about.component';

const routes: Routes = [
  { path: '', component: HomeComponent },
  { path: 'about', component: AboutComponent }
];

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

• Use the Angular CLI for project scaffolding and management.
• Organize files and modules logically.
• Write reusable components and services.
• Use Angular's built-in directives and pipes effectively.
• Implement lazy loading for larger applications.