Angular is a platform and framework for building single-page client applications using HTML and TypeScript. Developed and maintained by Google, Angular is a complete rewrite from the same team that built AngularJS. It provides a robust set of tools and features to create dynamic and responsive web applications.

1. Component-Based Architecture:

   • Angular applications are built using components, which are the basic building blocks of the UI.
   • Each component encapsulates its own HTML, CSS, and logic, making the application modular and maintainable.

2. TypeScript:

   • Angular is written in TypeScript, a superset of JavaScript that adds static typing and other features.
   • TypeScript helps catch errors early through type checking and provides better tooling support.

3. Dependency Injection:

   • Angular has a powerful dependency injection system that makes it easy to manage and inject dependencies.
   • This promotes code reusability and testability.

4. Two-Way Data Binding:

   • Angular supports two-way data binding, which means that any changes in the UI are reflected in the model and vice versa.
   • This simplifies the process of keeping the view and the model in sync.

5. Directives and Pipes:

   • Directives are special markers in the DOM that tell Angular to do something to a DOM element (e.g., show/hide an element, apply styling).
   • Pipes are used to transform data in the template (e.g., formatting dates, filtering lists).

6. Routing:

   • Angular's built-in router enables navigation between different views or pages in a single-page application.
   • It supports lazy loading, route guards, and nested routes.

7. Forms:

   • Angular provides robust support for building and managing forms, including template-driven and reactive forms.
   • It includes features like form validation and dynamic form controls.

8. HTTP Client:

   • Angular includes a powerful HTTP client for making HTTP requests to interact with backend services.
   • It supports features like interceptors, request/response handling, and error handling.

9. Testing:

   • Angular has built-in support for unit testing and end-to-end testing.
   • Tools like Jasmine, Karma, and Protractor are commonly used for testing Angular applications.

Let's create a simple "Hello World" application to understand the basics of Angular.

1. Install Node.js and npm:

   • Download and install Node.js from nodejs.org.
   • npm (Node Package Manager) is included with Node.js.

2. Install Angular CLI:

   • Open a terminal or command prompt and run the following command to install Angular CLI globally:

     npm install -g @angular/cli
     

1. Create a new project:

   • Run the following command to create a new Angular project named hello-world:

     ng new hello-world
     

   • Follow the prompts to set up the project (e.g., routing, styles).

2. Navigate to the project directory:

   cd hello-world
   

1. Serve the application:
   • Run the following command to start the development server:

     ng serve
     

   • Open a web browser and navigate to http://localhost:4200/. You should see the default Angular welcome page.

1. Open the app.component.ts file:

   • Navigate to src/app/app.component.ts in your project directory.

2. Modify the component:

   • Replace the existing code with the following:

     import { Component } from '@angular/core';
     
     @Component({
       selector: 'app-root',
       template: `<h1>Hello World!</h1>`,
       styles: []
     })
     export class AppComponent {
       title = 'hello-world';
     }
     

3. Save the file and observe the changes in the browser. You should now see "Hello World!" displayed on the page.

In this section, we introduced Angular, a powerful framework for building single-page applications. We covered its key features, including component-based architecture, TypeScript, dependency injection, and more. We also walked through a practical example of setting up a development environment, creating a new Angular project, and building a simple "Hello World" application.

In the next section, we will dive deeper into setting up the development environment and creating your first Angular app.