Angular Interview Questions and Answers

What is Angular?

Ans: Angular is a web development framework for both desktop and mobile applications. It is a lightweight, cross-platform platform development framework that provides powerful features for developers to create and manage web applications.

Angular was developed by Google as a replacement for the Karma web development tool in their Google Pages application framework. The framework was originally designed to be used with Page Speed Insights to monitor page load speed, but it can be used in any context where an Angular project might be found.

Angular has been designed to make developing and publishing web applications easy and fast by providing high-level design tools along with low-level functionality such as code generation, navigation, data management, etc.

The Angular team has made significant contributions to the framework, including:

• Andrew Green (Angular) is a Google Page Speed programme coder and lead developer.
• Mark Little – Program coder and lead developer at Google App Engine
• David Allen – Program coder & lead developer at Facebook Social Share API Development Group
  

Why was client-side frameworks like Angular introduced?

Ans: As web development has become more complex, developers have been turning to frameworks such as Angular and React for their development. These frameworks are used to drive the UI of an application and allow developers to build powerful applications that are teachable on the web.

Angular is a framework that was created by Facebook in 2013. It is a high-level framework designed for building web applications with JavaScript and HTML. It provides you with a set of APIs that make developing applications easy.

Angular’s main strengths lie in its ease of use and its ability to support both client-side and server-side rendering. The framework also comes with plenty of helpful documentation, making it perfect for beginners and advanced developers alike.

Explain the workings of an Angular application.

Ans: Angular is an open source web application development framework with a focus on high-quality and user-friendly applications. The framework provides a set of classes and methods for building HTML5-based web apps, as well as a set of tools to help you create and debug your applications.

When was Angular introduced? What is the latest version of Angular?

Ans: Angular was created by Google in 2015 to provide a better way to build high-quality websites that are easy to maintain, secure, and devoid of any styling or functionality changes. With the release of Angular 2 in 2016, the framework became more widely used among developers looking for an easier-to-use development platform.

Angular 3 is Google’s latest version of the web application framework with some major features including support for ES6 features such as let, map, flatMap, and await. It was released in June 2017 along with Angular 2 and Angular 1. At this stage, it’s not clear what impact these updates will have on the foundation itself; however, we do know that they’re likely going to add some more power to the framework’s API base, which has so far been lacking in modern browsers (e.g., tabs).

What is TypeScript?

Ans: TypeScript is a web development language created by Microsoft that was first released in 2015. It is a superset of JavaScript and is used to develop applications that run on both the desktop and mobile platforms.

TypeScript was created for developers who are new to web development and who are looking for a language that is easy to learn, but also has strong developer features such as type safety and rich functionality.

TypeScript has several advantages over JavaScript, including type safety, faster development speeds, ES6 syntax support, and better documentation. It also provides an environment for creating modern web applications with its TypeScript engine.

Angular architecture in a nutshell?

Ans: The architecture of Angular is shared below:

• Components and Templates
• Ng Modules
• Metadata
• Data Binding
• Directives
• Services
• Dependency Injection
  

What is metadata?

Ans: “Metadata” is the record of content or information that describes the nature, condition, and contents of an object. Metadata is attached in TypeScript using a decorator. It can be used to identify and categorize objects, extract data from videos or audio files, and more.

Explain the aim of the ngFor directive.

Ans: When there is a need to revise a section of an HTML template, then ngFor is used. Usually, it creates a template for each time as the repetition or iteration becomes more easily using ngFor directives.

What is the aim of the ngIf directive?

Ans: The prime aim of the ngIf directive is to remove a part of the DOM tree in alignment with an expression. Likewise, the element is discarded from the tree if the ngIf directive discovers that the expression is evaluated to be false; however, a matching element is appended to the DOM tree.

Briefly describe the template expressions.

Ans: Template expressions are a type of expression that allows for the creation of reusable code blocks. They allow for the development of reusable code that can be reused throughout the application. Template expressions allow developers to create and modify files in an easily readable format, which is necessary for unit testing. Additionally, template expressions can be used to create custom types and attributes that can be used throughout the application.

What are template statements?

Ans: Template statements are used to provide information for the user in a form that is easy to understand and easy to modify. They are used for both general and technical documentation.

Template statements consist of a set of instructions that are followed by the developer as they develop the application. The developer may or may not follow each template statement, but they all have one thing in common—they’re all instructions for developing an application.

Template statements can be written in any programming language, but most commonly they’re written in JavaScript or PHP. In addition to providing instructions for development, template statements can be used as documentation, that is, as part of the maintenance process of an application.

List the advantages of using Angular.

Ans: Angular is a web application framework that was created by Google. It was designed to make it easier for developers to create and maintain web applications.

It is based on the open-source NGINX TCP/IP internet server, which makes it easy to use and easy for other developers to add their own features.

• Angular separates the code into modules.
• It can be used to wrap functionalities like HTTP communication, data validation, routing, etc.
• Angular has a large ecosystem of tools, libraries, frameworks, plugins, etc.
• Angular makes the development experience much faster and more enjoyable

What is JQuery?

Ans: jQuery is an open-source web application development framework that was developed by an international team of developers. The framework was designed to be easy to use and easy to maintain, so it’s perfect for both new and experienced developers alike.

JQuery provides a rich set of features that make web development easier than ever before. JQuery is compatible with other programming languages such as JavaScript and HTML5, so you can easily add your own components to the framework.

Difference between Angular and Angular JS.

Ans:

Angular	AngularJS
Angular makes use of directives and components	AngularJS supports the Model-View-Controller or MVC model
Angular uses TypeScript language	AngularJS uses JavaScript
Angular uses () to bind an event while [] to bind a property	It requires professionals to use the correct ng directive to bind a property or an event
Angular provides mobile support	AngularJS does not provide mobile support
It uses @RouteConfig {(…)}	It uses $routeprovider.when()
Angular’ s simplified structure helps developer in creating large applications easily	Unlike Angular, Angular JSis less manageable

What are custom elements?

Ans: Custom elements are web application components that are created by the developer and can be used in their own right or as part of a larger design. They are typically used to display information within an application, or to provide additional functionality to an application.

List some of the most common custom elements.

Ans: The following is a list of some common custom elements:

Header – This element displays information about the website and is used for both branding and navigation. It can also be used for more detailed data collection within the website, such as user demographics or product details.

Footer – This element displays content about the website and is used for both branding and navigation. It can also be used for more detailed data collection within the website, such as user demographics or product details.

Site map – This element provides a visual representation of all content on a site, including pages that do not contain any content but which may contain data that is necessary to make the site function properly. The map can also be modified using JavaScript commands if required by users on the site themselves.

Contact form – This element provides an opportunity for users to contact their online service providers via email or phone under certain conditions (such as when they need help with an issue). It can also be modified using JavaScript commands if required by users on the site themselves.

Do I need to bootstrap custom elements?

Ans: No, you do not need to bootstrap custom elements, as they bootstrap automatically when added to the DOM.

Define typing for custom elements.

Ans: Defining typing for custom elements can be done by using NgElement and WithProperties.

@Component (…)

class MyDialog {@Input () content: string ;}

What is a custom pipe?

Ans: A custom pipe is an application that allows users to create and manage custom pipes. Custom pipes allow developers to provide a more customized experience for their users. They can include features such as security, logging, and reporting.

The framework provides a set of building blocks that are used to create custom pipes. The foundation of the framework is the CustomPipes library, which includes classes for creating and managing pipes, creating and managing routes, managing resources, and configuring development settings. The library also includes classes for handling requests, responses, error handling, and validation.

Brief bootstrapping module.

Ans:  A bootstrapping module is a web application development framework that makes it easy to create and maintain web applications. It provides developers with the tools needed to create and run their own websites.

The term bootstrapping refers to the process of creating a new, free-of-charge project that is designed to be used as an initial learning step before starting work on your own project. The term “bootstrap” is a popular theme for this type of project.

Define Module.

Ans: A module is a collection of files that are bundled together with other files in order to make up an application or website. A module can include code, CSS, JavaScript, images, and other assets that are required by the website being developed (the assets package). The contents of the assets package determine what styles will be applied when page content is rendered on the page being developed; this includes fonts, colors, graphics (including image file sizes), and text styles.

Explain how to use HttpClient with an example.

Ans: To use the HttpClient, follow below-shared steps:

• Create an HTTPClient instance.
• Create an instance of functions.
• Command HttpClient to run the functions.
• Read the response.
• Now launch the connection.
  

How can you read the full response?

Ans: In order to read the full response in Angular, the following code should be used:

Code:

GetUserResponse (): Observable<HttpResponse> {

returnthis.http.get (

this.userUrl, {observe: ‘response’});

}

What is “content projection”?

Ans: Content projection” is an open-source web application development framework that enables developers to create and run content-based websites.

It refers to a pattern in which developers can insert content into a different component.

How do you perform Error handling?

Ans: Error handling can be accomplished by writing a function that uses HttpClient and catchError from RxJS.

What do you mean by data binding?

Ans: Data binding is the process of changing one object’s state (e. – data), or values, to another object’s state (a – value). You can bind values to an object using either a static or dynamic property.

Data binding is useful because it allows you to change the properties of an object without having to modify the objects code. It also makes it easier for developers to change the properties and values of an object without having to modify the application code.

List the types of data binding in Angular.

Ans: Listed below are the four types of data binding in Angular:

• Event binding
• Property binding
• String interpolation
• Two-way data binding

What are some disadvantages of using Angular?

Ans: Some disadvantages of Angular are:

• There is no standard way to package angular modules into packages, making it difficult to install them on the command line without knowing how to build and install packages.
• The framework itself is quite new, and not all features will work as expected, making it difficult for beginners to use Angular for their projects.
• The framework does not provide a lot of support outside of the developer community, so there may be limited knowledge about Angular available locally on the internet (e.g., Stack Overflow).

What do you mean by “string interpolation”?

Ans: String interpolation is a technique used in web applications to allow users to enter values into fields without having to manually enter the value into the field. It is an important technique for developers because it allows them to easily add functionality without requiring users to manually enter data into the fields.

List the differences between Angular decorators and annotations.

Ans: Decorators are design patterns that help in the modification or decoration of classes without making any changes to the main source code.

Annotations, on the other hand, are used to construct an annotation array. Annotation is a type of metadata that makes use of the Reflective Metadata library.

What is an AOT compilation in Angular?

Ans: An AOT (Ahead of Time) compilation is an Angular module that contains the runtime components and stylesheets used to create your app’s UI. An AOT compilation is performed by adding a “.angular-compiler” file to your app’s .configure script or by using the ng new.

What are the advantages of AOT?

Ans:  Here are some advantages of AOT shared below:

• AOT is a web application development framework that supports JavaScript and CSS.
• It is designed to make developing web applications easy and fun.
• The framework features powerful features such as dynamic loading, file management, and Ajax support.
• The compiler will minify the code to make the download size smaller.
• AOT can render the application immediately without compiling the app.
• It also includes Node.js development tools like NPM and Bower along with a number of other tools that are useful for creating website content.

List the three phases of AOT.

Ans: The three phases of AOT are:

• code analysis
• code generation
• template type checking
  

List out the components in Angular.

Ans: Angular includes a set of JavaScript modules (JavaScript packages) that can help you create websites, apps, and pages. These modules are used in conjunction with the rest of the framework to make up an application’s code base. The more packages you add to an application’s source code base, the more easily it will be able to run on any platform that has JavaScript running on it. You can also install Angular CLI commands via npm or yarn if you prefer.

What are dynamic components?

Ans: Dynamic components in the Angular framework can be explained as the components that help in developing large-scale applications easily.

Explain the purpose of base href tag.

Ans: The href attribute is used to specify the base URL for all the related URLs on a web-page. The base href tag is utilised as a base route to the component, template, and module files.

What is the Document Object Model in Angular?

Ans: Document Object Model is a framework used in AngularJS to store and retrieve data in model objects.

To store and retrieve data in model objects, a document object model is used. This can be useful for creating model objects that can be used with other frameworks or languages, such as ERP or SQL.

What does an Angular document model package contain?

Ans: The angular-document-model package contains classes that are used to create and manage document object models (DOMs). These classes include angularDOM, angularModel, angularModelFactory, and angularModeFactoryService.

What is the difference between jQuery and Angular?

Ans: The prime difference between jQuery and Angular is:

• jQuery is a JS library, while Angular is a JS frontend framework.
• Angular offers form validation; JQuery does not.
• Angular offers two-way binding, while JQuery does not.

What are templates?

Ans: Angular templates are written using HTML that has attributes and elements, and later the templates are combined with data to offer the end-user a dynamic view.

What is two-way data binding?

Ans: Two-way data binding is to make sure that the data model is automatically synchronized. It means that there is a sharing of data between a component class and its template. Furthermore, if there is a change in data at one location, the change automatically reflects at the other locations.

What is RxJS?

Ans: RxJS stands for Reactive Extensions for JavaScript. It is a library that is used in many renowned frameworks, like Angular. It allows developers to compose callback-based code into a series of operations. Many other languages, like Python, also have libraries that allow them to write reactive code with the help of observables.

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Explain the digest cycle process in Angular.

Ans: The digest cycle can be explained as a process in which the watch list is examined to track all the changes in the watch variable value.

What is REST?

Ans: The acronym for REST in Angular is Representational State Transfer. REST is an API that works on the request of HTTP . In a nutshell, when an end-user makes any request, then the API returns the response or value on the web page upon request via HTTP.

What is the scope?

Ans: In Angular, a scope can be defined as an object, such as an application model. Scope is a context for executing expressions and supports propagating other events.

Define schematics in Angular.

Ans: A schematic is nothing but a code generator; it alters a software project by modifying codes.

Briefly describe the angular schematics rule.

Ans: The rule of schematic in Angular is simple and straight; it takes a tree, modifies it, and creates a new tree.

What exactly is an HTTP client?

Ans: HttpClient is an Angular module that manages HTTP requests between your website and third-party services. It is used by websites to make requests to third-party services like email clients, social media apps, etc.

HttpClient has been adopted by thousands of developers around the world. HttpClient returns the data as an observable, which can be subscribed to or unsubscribed.

What is the role of the SPA in Angular?

Ans: The SPA is an open-source web application development framework that was developed by the Angular team to make developing, deploying, and managing web applications easier. The framework provides highly expressive APIs for building and deploying web applications. It makes it possible to build, deploy, and manage any kind of website in a way that has never been possible before.

Benefits of SPA in Angular

The SPA Framework provides a set of APIs for building and deploying web applications that are well suited for creating, maintaining, and testing websites. The framework also includes APIs for testing your code on different platforms, so you can test your website on different devices without having to change the code base on which the website runs.

Because the SPA Framework can be used in both desktop and mobile environments, it is ideal for developers who work in either environment or who want to develop websites using the framework without knowing any specific environment or platform.

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