What are the Popular Angular Interview Questions?
11.16.2023
What Are the Most Popular Angular Interview Questions?
Angular is a highly popular framework among web developers worldwide. This component-based framework is widely used to build scalable web applications. It addresses the challenges faced by developers through its end-to-end tools and enables the use of multiple technologies simultaneously, making it a sought-after tool in modern application development.
If you're a developer preparing for a technical job interview, understanding the most commonly asked Angular interview questions and answers is crucial. Even if you're not preparing for an interview but are new to web development, these questions can serve as a valuable guide in your journey. They cover fundamental concepts, Angular's key features, and insights into current technologies. Expect interview questions on topics like JavaScript, TypeScript, Angular Framework, HTML/CSS, and RxJS.
Most Frequently Asked Angular Interview Questions and Answers
1) What is Angular?
Angular is an open-source JavaScript framework written entirely in TypeScript. It uses HTML syntax to clearly define application components and is designed for creating Single Page Applications (SPAs). Angular adds structure, consistency, scalability, and maintainability to web pages.
2) What Technologies Does Angular Use?
Angular is a front-end JavaScript framework developed by Google. It leverages various technologies to simplify specific tasks and improve the development experience. In addition to working with TypeScript, Angular also utilizes RxJS.
3) How Does Angular Work?
Angular begins its process with the ANGULAR.JSON configuration file, which provides paths, configurations, and the main file for the application. It then uses MAIN.TS as the entry point for setting up the browser environment, enabling the application to run.
The client-side operation of Angular applications follows these steps:
- Initialization: Angular bootstraps the root component, which serves as the entry point.
- Component Rendering: Components are rendered based on predefined templates, each containing a structure and layout for the user interface.
- Data Binding: Angular facilitates synchronization between the component's model and the view, ensuring real-time updates.
- Component Interaction: Components communicate through inputs, outputs, and services to exchange data and functionality.
- Event Handling: Angular captures and processes user interactions like button clicks and form submissions.
- Dependency Injection: Angular uses dependency injection for modularity and to simplify integrating reusable code modules.
- Routing: The routing module enables navigation by defining which components appear based on the current URL.
- Compilation: Files are compiled to reduce file size and improve performance.
- Deployment: The compiled application is hosted on a web server or hosting platform.
4) What Are the Advantages of Angular?
Angular allows developers to write powerful, structured code that compiles to JavaScript. It supports modular development for tasks like HTTP communication, data validation, and routing. Angular also boasts an extensive ecosystem of tools, libraries, frameworks, and plugins such as CLI, NgRx, and RxJS, enhancing the development experience.
5) What Are the Disadvantages of Angular?
While Angular improves productivity, it requires additional configuration for SEO optimization. Its extensive feature set can also make the learning curve steep. Additionally, the framework can increase JavaScript bundle size, making it less ideal for small-scale projects.
6) What is TypeScript?
TypeScript is a superset of JavaScript that enhances consistency and maintainability. It introduces features like types and classes, which Angular uses to compile into JavaScript. This makes features accessible across various environments.
7) What is RxJS?
RxJS, short for Reactive Extensions for JavaScript, is a library that facilitates reactive programming. It’s commonly used in Angular as well as other popular frameworks.
8) What is Data Binding?
Data binding enables users to modify web page elements through their browser without complex programming. It uses dynamic HTML and is often applied in interactive web page components like forms, calculators, and games. In Angular, data binding connects the component and DOM, making it easier to create interactive applications without manual data manipulation.
9) What is Metadata?
Metadata in Angular describes how a class should be processed. A class behaves as a regular class until introduced via metadata. This metadata is added using decorators, which define configurations and operational instructions for classes.
10) What Are Single Page Applications (SPAs)?
SPAs are web applications that load once and dynamically update content without reloading new HTML pages. JavaScript dynamically modifies the existing page's DOM, providing a seamless user experience.
11) What Are the Differences Between Angular and AngularJS?
| Feature | AngularJS | Angular |
| Language | JavaScript | TypeScript |
| Mobile Support | None | Supports all popular mobile browsers |
| Architecture | MVC (Model-View-Controller) | Components and directives |
| Dependency Injection | Not supported | Supported |
| Routing | Uses @routeProvider | Uses @Route |
| Management | Hard to manage due to code size | Easier to manage for large applications |
12) What Are Angular Decorators?
Decorators in Angular define how its features function. They are functions used to modify components, services, or filters before runtime. Angular supports four types of decorators:
- Class Decorators
- Method Decorators
- Parameter Decorators
- Property Decorators
13) What Are Angular Templates?
Angular templates are HTML structures with Angular-specific elements and attributes. Combined with data from the model and controller, templates provide users with dynamic views.
14) What is a Dependency Hierarch?
Angular’s dependency hierarchy is built using Dependency Injection (DI). DI manages dependencies within an application, and the hierarchy works as follows:
- Defining Dependencies: Components specify their dependencies via TypeScript types or decorators.
- Registering Dependencies: Providers in Angular handle creating and managing instances of dependencies.
- Resolving Dependencies: DI examines constructors and resolves dependencies by searching the injector hierarchy.
15) What is Angular Dependency Injection’s Hierarchical Approach?
The DI system follows a hierarchical approach, where each component has its injector. If a requested dependency isn't found in the current injector, Angular searches parent injectors recursively until it finds a match or reaches the root.
16) What Are Annotations in Angular?
Annotations in Angular are metadata used to create a description for a class. They define how Angular processes the class.
17) What Are Angular Directives?
Directives allow custom HTML syntax in applications. Angular supports three types of directives:
- Structural Directives
- Attribute Directives
- Component Directives
18) What is AOT Compilation?
Ahead-of-Time (AOT) compilation translates Angular HTML and TypeScript code into JavaScript during the build process. Benefits include:
- Faster rendering
- Template error detection
- Enhanced security
- Smaller framework download sizes
19) What Are Pipes?
Pipes are simple functions designed to transform input values and return them as output. Angular provides built-in pipes and allows custom pipe creation.
20) What Are Pure Pipes?
Pure pipes are invoked only when the input value or parameters change.
21) What Are Impure Pipes?
Impure pipes are called for every change detection cycle, regardless of whether the input or parameters have changed.
22) What Are Filters in Angular?
Filters format and present expressions to users. Common filters include:
- Date Pipe: Formats dates.
- Json Pipe: Converts objects into JSON strings.
- Uppercase Pipe: Transforms text to uppercase.
23) What is View Encapsulation?
View encapsulation determines whether styles defined in a component affect the entire application. Angular provides three strategies:
- None: Styles apply globally.
- Native: Styles are limited to the component.
- Emulated: Styles affect both the component and global HTML.
24) What is the Angular Lifecycle?
Each Angular component has a lifecycle. Hooks can modify this lifecycle:
- ngOnChanges: Triggered when input properties change.
- ngDoCheck: Invoked for custom change detection.
- ngOnInit: Called when the component initializes.
- ngAfterContentChecked: Called after content projection into the component.
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