Angular 4 Interview Questions: Crack Your Next Angular 4 Interview

Introduction

Angular 4 is a popular web development framework used for creating dynamic and responsive web applications. As the demand for Angular 4 developers is increasing rapidly, it is essential to prepare well for the interviews to increase your chances of getting hired. In this article, we will cover some of the most commonly asked Angular 4 interview questions with detailed answers to help you prepare for your next interview.

Angular 4 Interview Questions and Answers

1. What is Angular 4?

Angular 4 is an open-source web development framework developed and maintained by Google. It is a complete rewrite of the AngularJS framework and comes with various improvements, including faster performance, improved load time, and smaller bundle sizes.

2. What are the new features introduced in Angular 4?

Some of the new features introduced in Angular 4 are:

1. Animation Package: A new animation package that enables the creation of smooth and powerful animations.
2. ngIf and ngSwitch: Improved ngIf and ngSwitch directives that make it easier to write template code.
3. Template Reference Variable: A new syntax for declaring template reference variables.
4. HttpClient: A new way to make HTTP requests that is more user-friendly and less error-prone.

3. What is the difference between AngularJS and Angular 4?

AngularJS is the first version of the Angular framework, while Angular 4 is a complete rewrite of AngularJS. Some of the major differences between the two are:

1. Performance: Angular 4 is faster and more efficient than AngularJS.
2. Bundle size: Angular 4 has a smaller bundle size, making it faster to load and easier to use.
3. Improved directives: Angular 4 has improved directives like ngIf and ngSwitch that make it easier to write template code.
4. TypeScript: Angular 4 is built on TypeScript, which is a superset of JavaScript, making it easier to write and maintain code.
5. 4. What is the difference between Angular and React?
6. Angular and React are both popular web development frameworks, but there are some differences between the two:
7. Language: Angular is built on TypeScript, while React is built on JavaScript.
8. Architecture: Angular follows a component-based architecture, while React follows a unidirectional data flow architecture.
9. Performance:  Angular is faster than React, but React is more lightweight and easier to use.

What is a directive in Angular 4?

A directive in Angular 4 is a reusable piece of code that can be applied to any element in a template to modify its behavior or appearance. Angular provides several built-in directives such as ngIf, ngFor, and ngClass.

What is a service in Angular 4?

A service in Angular 4 is a reusable piece of code that provides functionality to other parts of an application. Services can be used to share data between components, perform HTTP requests, or interact with external APIs.

What is dependency injection in Angular 4?

Dependency injection is a design pattern used in Angular 4 to provide dependencies to components and services. In Angular, dependencies are declared in the constructor of a component or service, and they are automatically injected by the framework.

What is a module in Angular 4?

A module in Angular 4 is a logical unit of code that encapsulates related components, directives, and services. Modules can be used to organize an application into smaller, more manageable pieces.

What is lazy loading in Angular 4?

Lazy loading is a technique used in Angular 4 to load modules on demand, only when they are needed. This can improve the performance of an application by reducing the initial load time.

What is an observable in Angular 4?

An observable in Angular 4 is a type of data stream that allows components to react to changes in data over time. Observables can be used to manage asynchronous data flows, such as HTTP requests.

 Are you preparing for an Angular 4 interview? Check out this article to learn about the most frequently asked Angular 4 interview questions and their answers.

What is the difference between async and defer in script loading?

Async and defer are attributes that can be used in script tags to control when and how the script is loaded. Async scripts are loaded asynchronously, while defer scripts are loaded in order, after the page has finished parsing.

What is AOT (Ahead Of Time) compilation in Angular 4?

AOT compilation is a technique used in Angular 4 to compile an application's TypeScript and template code into optimized JavaScript code at build time, rather than at runtime. This can improve an application's performance and reduce its initial load time.

What is zone.js in Angular 4?

Zone.js is a library used in Angular 4 to provide a context for asynchronous operations such as HTTP requests, timers, and event listeners.