Top 44 TCS Angular Interview Questions and Answers [2024]
Angular is one of the most popular front-end JavaScript frameworks used for building dynamic and modern web applications. As a result, many companies, including TCS (Tata Consultancy Services), are actively looking to hire Angular developers. If you are preparing for an interview at TCS or any other company that uses Angular, it is essential to be prepared with some commonly asked questions. In this blog, we have compiled a list of top TCS Angular interview questions and answers for developers that will help you ace your next job interview in this field.
Common TCS Angular Interview Questions for Beginners
Here are common Tata Consultancy Service (TCS) angular developer interview questions and answers for entry-level candidates:
Q1. Define Angular and discuss why it was created.
Answer: Angular is a TypeScript-based open-source web application framework led by the Angular Team at Google and a community of individuals and corporations. It was created to address challenges with building complex, interactive, and scalable web applications. The framework aims to simplify the development process, enable a modular architecture, provide an ecosystem of tools/libraries, and streamline client-side development.
Q2. Enumerate the advantages of using Angular.
Answer: Some advantages of Angular include:
- It helps users build modular and scalable applications using components.
- Provides high performance through optimized code generation.
- Enables faster development through strong tooling and integration capabilities.
- Supports reusable UI components such as web components.
- Powers native mobile apps using frameworks like NativeScript.
Q3. Explain the concept of data binding in Angular.
Answer: Data binding is a process that enables users to interact with various elements on a web page through their internet browsers. It makes use of dynamic HTML and does not require advanced scripting or coding skills.
This functionality is commonly used in web pages featuring interactive components like forms, calculators, tutorials, and games. This feature is particularly useful when dealing with large amounts of data on a webpage as it allows for an incremental display approach.
Q4. Explain the concept of templates in Angular.
Answer: In Angular, templates serve as a blueprint for a specific part of the user interface. These templates are written in HTML and have access to various features within Angular through special syntax.
They display data through interpolation and directives. They also handle user interactions through event binding. Templates are linked to their component class which manages the data and logic.
Q5. Provide a brief explanation of Single Page Applications (SPAs).
Answer: Single-page applications are web apps that dynamically update sections of a page without requiring a full page reload. This creates a smooth user experience similar to a native app. SPAs utilize client-side JavaScript frameworks like Angular to manage UI logic and updates. They request necessary data using APIs and render updates on the front end itself.
Q6. In Angular, what is the function of annotations?
Answer: When working with Angular, annotations (also referred to as decorators) are responsible for attaching metadata to a class or its members. These annotations provide valuable information to the Angular compiler, allowing it to configure the class and its members accordingly.
For example, the @Component() decorator marks a class as an Angular component. Similarly, @Input() and @Output() define a property or event as an input or output binding. This metadata enables Angular to interpret components correctly.
Q7. What are angular directives and how do they work?
Answer: Angular directives are classes that add additional behavior to elements in the document object model (DOM). Directives have a selector that binds them to one or more HTML tags. They also contain a template and logic that defines its functionality and how it handles data. Some examples are structural directives like *ngIf, *ngFor, and attribute directives like ngModel.
Q8. Define AOT compilation and outline its benefits.
Answer: AOT (Ahead-Of-Time) compilation precompiles Angular component templates during the build process. This results in faster rendering and smaller bundle sizes and detects template errors during build instead of runtime. It also improves security by reducing injection vulnerabilities and improves overall performance.
Q9. What is the concept of the PipeTransform interface?
Answer: The PipeTransform interface needs to be implemented by any custom pipe in Angular. This interface defines the transform() method that performs the actual transformation logic based on input parameters. Some examples of built-in Angular pipes are DatePipe and JsonPipe.
Q10. Describe the purpose of pipes in Angular.
Answer: Pipes are used to transform various types of data, such as strings, currency amounts, and dates for better presentation. These functions are easy to incorporate in template expressions and take an input value, which is then converted into a transformed output value.
The advantage of using pipes is in their versatility, as they can be utilized anywhere within the application without having to declare them multiple times.
Q11. Define the concept of router links in Angular.
Answer: Router links help navigation between pages by linking to specific routes defined in the routing module. It opens one or more routed components in <router-outlet> locations on the navigation page.
Q12. What does the term “router state” refer to in Angular?
Answer: A router state is a configuration of application elements that determine the content displayed on the screen. It is defined as the state of the router as a tree of activated routes. It represents the router state as it keeps changing according to how users navigate from page to page.
Q13. Explain the significance of Angular Material.
Answer: Angular Material offers a cohesive and consistent design system that closely follows the guidelines of Google’s Material Design. This promotes a seamless user experience throughout your application, regardless of its complexity or team size.
Q14. Describe the purpose of HTTP interceptors in Angular.
Answer: Angular’s HTTP Interceptors are implemented as classes that conform to the HttpInterceptor interface, allowing for a multitude of tasks involving HTTP requests and responses. These include adding headers, managing errors, altering request or response data, logging events, implementing authentication measures, and more.
Q15. How do you handle errors in observables?
Answer: When working with observable errors in Angular, the catchError operator is a useful tool for managing and resolving these issues. It offers the ability to handle errors by providing an alternative value or executing different code when one occurs. By placing this operator after any potential error-generating observables, you can specify a function that will be called upon encountering an error. This allows tasks such as logging the error, displaying it to users, or attempting retries if necessary within the callback function.
Also Read: TCS Java Interview Questions
TCS Angular Interview Questions for Mid-level Executives
Here are the top TCS Angular interview questions and answers for candidates with relevant experience using the Angular framework:
Q16. What exactly is TypeScript?
Answer: TypeScript is an open-source typed superset of JavaScript created by Microsoft that compiles plain JavaScript. It adds additional features like static typing, classes, interfaces, generics, etc. to JavaScript.
Also, using TypeScript enables users to build complex web apps that scale while retaining compatibility with all JS environments. Angular itself is written in TypeScript and uses it extensively.
Q17. Explain the purpose of decorators in Angular.
Answer: Decorators are functions that alter the behavior of a class without altering its core code. They are commonly used in design patterns and can be found in AngularJS, where they are known as functions that manipulate services, directives, or filters.
Q18. What are the key updates introduced in Angular 10?
Answer: Among many others the latest updates include:
- Improved compiler speed and reduced application size
- TypeScript 3.9 support
- Stricter typing for TemplateRef
- New ng server CLI command
- Optional ng add for libraries
- Updated Angular Material and CDK
Q19. How would you describe impure pipes?
Answer: Impure pipes are executed on every change detection cycle even when the input parameters have not changed. They perform complex logic so the pipe needs to be re-invoked during CD runs to allow dependent properties to update. Examples of impure pipes include JsonPipe and DatePipe.
Q20. In simple terms, what are filters in Angular? Can you provide a few examples?
Answer: Angular filters are a useful tool for altering the appearance of an expression’s value without modifying its original format. For instance, if you need to display a string in lowercase or uppercase, AngularJS provides filters to easily accomplish this task.
Q21. Define an ngModule.
Answer: An ngModule is a special type of class decorated with the @NgModule decorator. This decorator contains a metadata object that provides instructions on how to compile the template of a component and create an injector during runtime.
Q22. Explain the characteristics of pure pipes in Angular.
Answer: Pure pipes operate only when the input value reference changes. Their output is cached and the pipe is only re-invoked when the input reference changes. This improves performance. Examples of pure pipes include UpperCasePipe, LowerCasePipe, etc.
Q23. Describe the concept of components in Angular.
Answer: Components are the main building blocks used to create the UI in Angular applications. They control sections of the screen called views. Components have a TypeScript class controlling logic, an HTML template defining the UI, and component decorator metadata providing info to Angular.
Q24. Explain the concept of view encapsulation in Angular.
Answer: View encapsulation defines how the styles (CSS) of an Angular component are applied to its template. There are three encapsulation strategies:
- Emulated (default): It emulates shadow DOM by adding unique attributes to component CSS selectors for isolation.
- Native: It uses the browser’s native shadow DOM implementation for CSS isolation.
- None: Component CSS applies globally across the whole application.
Encapsulation ensures the component styles apply only to that component’s template without affecting other components to prevent clashes.
Q25. Define controllers and their role in Angular.
Answer: AngularJS controllers are responsible for managing the data in AngularJS applications. They operate as regular JavaScript objects and are defined using the ng-controller directive. However, controllers are part of the outdated AngularJS (Angular 1) architecture.
In the current versions of Angular, controllers don’t exist. Components and services are currently working in their role:
- Components handle the UI logic and data for their template.
- Services manage shared application data and logic across components.
The component-service architecture in modern Angular provides a cleaner separation over controllers. Components focus on their UI while services manage reusable data and logic.
Q26. What methods are available for sharing data between Angular components?
Answer: Methods for sharing data between components are:
- Using Input and Output Decorators
- Using NgRx
- RxJS Subjects
- Using Local Storage or Session Storage.
Q27. Explain the purpose and function of RxJs in Angular.
Answer: RxJS is a popular library designed for reactive programming through the use of observables. This tool simplifies creating asynchronous or event-driven programs by offering a wide range of useful operators.
Q28. What defines a parameterized pipe in Angular?
Answer: Parameterized pipes accept arguments to transform their input value and display formatted output. For example, date pipes.
Q29. What functionalities do class decorators offer?
Answer: Angular offers a set of class decorators that allow users to specify the role of a particular class, such as being a component or module. Additionally, these decorators enable us to define an effect without having to include any code within the corresponding class using @DecoratorName syntax.
Q30. How are method decorators utilized in Angular?
Answer: Method decorators are a way to add additional functionality to methods within a class. A popular example of this is the @HostListener decorator, which can be used to listen for events on a specific element in our component’s template. This allows users to easily extend and enhance the behaviour of their methods without having to modify their original implementation directly.
Also Read: TCS Python Interview Questions
Advanced TCS Angular Interview Questions for Experienced Candidates
Here are the best TCS Angular interview questions for experienced candidates:
Q31. Define Angular services and their role in the framework.
Answer: Angular services allow users to isolate data and functions within their app, which makes data easily accessible for multiple components. For a service to be shared among different components, it must first be made injectable. Once injected into a component, the service becomes a dependency of that specific component.
Q32. Specify the type of Document Object Model (DOM) implemented by Angular.
Answer: Angular applications are powered by a virtual DOM rather than the browser’s native DOM implementation. The virtual DOM is a fast in-memory representation of UI elements as JavaScript objects. Angular’s change detection keeps the virtual DOM in sync with the component state.
Q33. Explain the concept of Bootstrap and how it integrates with Angular.
Answer: Bootstrap is a popular CSS framework providing design templates for components like navigation bars, buttons, modals, etc. In Angular, users can integrate Bootstrap in three ways:
- Use pre-built Angular Bootstrap components
- Include Bootstrap CSS in styles
- Write custom directives for Bootstrap plugins
This allows users to easily build responsive UIs by leveraging Bootstrap styles.
Q34. Explain the concept of dependency injection in Angular.
Answer: Dependency injection (DI) is a crucial aspect of the Angular framework that facilitates components in accessing services and other essential resources. Within Angular, users can inject a service into a component for the component to have access to it.
Q35. Explain the characteristics of both template and reactive forms in Angular.
Answer: Here are the characteristics of both template and reactive forms in detail:
Template Forms:
- Based on a model-driven approach where form control and validation logic is defined directly in the template using directives like ngModel, required, minlength, etc.
- Simpler and less explicit and requires less code. They are faster to implement in simple scenarios.
- With two-way binding between the form, model, and view, values are updated directly between the view and model.
- State managed as template reference variables.
- Testing is harder as behavior is tied to a template.
Reactive Forms:
- This model is immutable, and explicitly defined in the component class.
- More control from component code, all logic resides in the component class.
- Unidirectional data flow between model and view.
- Asynchronous validation.
- State stored in observable FormControl instance.
- Better testability as most logic is in the component class.
- Complex asynchronous workflows are easier.
- More explicit and requires more code.
Q36. Define eager and lazy loading in Angular.
Answer: Angular provides two primary loading techniques: eager and lazy. With eager loading, all modules are loaded upon startup. Whereas with lazy loading, modules are only loaded when their corresponding routes are accessed on-demand. However, lazy loading leads to faster load times.
Q37. Describe the functioning of an Angular application.
Answer: Angular is a platform that offers developers the necessary tools to create dynamic web applications efficiently. This includes a component-based framework designed for scalability and an extensive range of integrated libraries covering various functionalities, such as routing, form management, and client-server communication.
Q38. Differentiate between Ahead-of-Time (AOT) and Just-in-Time (JIT) compilation in Angular.
Answer: The default option for compilation is JIT, which works well for smaller projects and development purposes. However, AOT compilation provides higher performance and is more suitable for larger projects or production settings. Here are some basic differences:
| AOT Compilation | JIT Compilation |
| Occurs during build time Detects template errors during compile time Improves application performance Faster rendering speed since compilation is already done | Occurs dynamically during runtime Harder to detect template errors Can increase application size Allows dynamic runtime compilation |
Q39. How do you share data between components in Angular?
Answer: Some ways to share data between Angular components:
- Parent-to-child data sharing using @Input decorator
- Child-to-parent sharing using @Output decorator and EventEmitter
- Sharing using services that act as centralized data stores
- Leveraging RxJS subjects like BehaviourSubject for observable streams
- Shared stat using centralized state management like NgRx Store
Q40. Explain MVVM architecture
Answer: MVVM, short for Model-View-ViewModel, is a widely used architectural pattern in software development. Its purpose is to separate the graphical user interface (view) from the business logic or back-end code (model).
This separation allows users to easily maintain and modify both components without affecting each other’s functionality. Whether through using markup language or GUI code, MVVM ensures that changes made to one component do not affect the other.
Q41. What inspired the introduction of client-side frameworks like Angular?
Answer: The need for building complex, scalable, and interactive web apps led to front-end JavaScript frameworks like Angular that simplify development.
Q42. Elaborate on how an Angular application operates.
Answer: Angular utilizes a component-based architecture, where large applications are divided into smaller functional and logical components. This approach allows for the reusability of these components throughout different parts of the application.
Q43. Define components, modules, and services within the Angular framework.
Answer: The key role of a component is to display a visual representation and manage user interactions for that view. In contrast, modules encompass services, pipes, and additional code utilized by the components within its scope. A class and template are used to define a component, whereas an Angular NgModule decorator defines a module.
Q44. How is Angular different from JavaScript?
Answer: AngularJS and JavaScript are commonly used in web development, but they serve distinct purposes. AngularJS is a framework that facilitates the creation of single-page web applications, whereas JavaScript is a programming language suitable for building both web and mobile apps.
Also Read: TCS Ninja Programmer Interview Questions and Answers
Important Tips to Ace TCS Angular Developer Interview
Below are tips to help you ace your TCS Angular developer interview questions:
1. Practice Answers
Familiarizing yourself with common TCS Angular interview questions for coders is important. Make short notes or bullet points to refer to during the actual interview. Also, practicing answering common interview questions aloud while looking in a mirror can help get comfortable and organize your thoughts. This preparation will allow you to cover all necessary information confidently during your interview process.
2. Arrange Mock Interviews
If you have some spare time, try practicing mock interviews with a friend or family member. This exercise can enhance your ability to answer both simple and complex coding questions through repetition, while also improving your interview body language.
3. Build Your Interview Skills
Interviewers pay attention to more than just your technical skills during an interview. They also take note of how well you utilize other important skills such as active listening, engaging in small talk, and showing empathy. These skills will leave a positive impression on the interviewer and can also provide them with insight into what it would be like to have you as an employee.
Conclusion
Our comprehensive list of TCS Angular interview questions and answers for developers covers a wide range of topics that assess your expertise in the Angular framework. Apart from testing your technical skills, these questions also evaluate problem-solving abilities. It is essential for you to thoroughly prepare yourself by practicing coding exercises, revising concepts, and familiarizing yourself with common issues encountered while working with Angular before your TCS interview process.
If this has been helpful to you, leave us your thoughts and feedback in the comment section below. Also, check out this quick guide on mastering interview etiquette to adequately prepare you for your interview.
