Angular 4 Interview Questions and Answers

Last updated on Feb 07, 2024
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Angular 4 Interview Questions

Angular 4, released in March 2017, is a JavaScript framework for building apps in HTML, JavaScript, and TypeScript. Angular 4 offers built-in features for HTTP service, animation, and materials. This is an essential topic in the Angular 4 Interview Questions for experienced professionals. The unique feature in Angular 4 is that starting from Angular 4, developers will be able to query ParamMap in the router.

Quick Facts About Angular 4
What is current angular version? Angular 11.0. released on 11th November 2020
Angular4 is Developed by Google
What language does Angular use? TypeScript
When was Angular first released? 20th October 2010
When was Angular4 released? 23rd March 2017
Which is the best free IDE for Angularjs? Sublime Text, Visual Code, Atoms, etc
What is the best Angular version of web development? For the development, Angular 2 and 4 both are good.

Most Frequently Asked Angular 4 Interview Questions

Here in this article, we will be listing frequently asked Angular 4 Interview Questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.

Q21. What do you mean by observables and promises?

Promises help to function with asynchronous operations. They work in two conditions. They either return a single value when the promise resolves or an error message when the promise gets rejected. Whenever a request is made from a promise, it becomes a non-cancellable command.

On the other hand, observable can be regarded as a stream. It can be anything, a stream of data or events. It can be canceled, unlike promise. An observable can be easily converted into a promise by specifying a command “toPromise( )” with the command to do so.

Q22. Explain different types of component decorators In Angular 4?
In Angular 4, there are four types of component decorators:
  • Class decorators
  • Property decorators – used for properties inside classes
  • Method decorators – used for methods inside classes
  • Parameter decorators – used for parameters inside class constructors

This information is usually asked in interview questions on Angular 4.

Q23. What is the template statement Angular? Explain with a syntax.

A template statement in Angular is used to respond to an event raised by a binding target, element, component or directive. Here is the syntax of a template statement:



Q24. How do you use string interpolation Angular 4?

String interpolation in Angular is a one-way data-binding technique used to take the output data from a typescript code and into an HTML template. It uses the template expression through double curly braces {{ }} displaying the data from a component to view.

Here’s an example to show you how to use String Interpolation:

import {Component} from ‘@angular/core’;
selector: ‘app-root’,
styleUrls: [‘./app.component.css’]
export class AppComponent {
title=’string interpolation in tutorialandexample’;

Q25. How to install Angular 4?
There are various ways available to install Angular 4.
  • Install the Angular CLI
    npm install -g @angular/cli
  • Create a Project
    ng new MyApp
  • Serve the application
    cd MyApp
    ng serve --open

This information can be asked during angular 4 interview questions.

Q26. What is the use of TypeScript in Angular 4?
TypeScript is the native language for Angular Development. It has Design-time support for Tooling and Type Safety and is basically a superset of JavaScript.
Q27. What is routing in Angular 4?

Routing essentially means navigation in-between pages. Sites having links redirecting you to another page is called routing in Angular 4.

Q28. What is guard in Angular 4?

In Angular 4, functionalities, logic and code which are executed before the loading of a route is called Guards. Guards check the route access, child route access, new feature in a module and prompt the user of any unsaved changes.

Q29. What is the use of CanActivate in angular 4?

CanActivate is a feature in the Angular Interface focused on security. It prompts the user to login to the application during the routing of a page.

Q30. What is lazy loading?

Lazy Loading is a popular method used in Angular 4 which is used to load JavaScript components asynchronously when a specific routing feature is activated. Its main use is to increase performance during the initial load within a complex routing scheme involving multiple components.

This means a request for the route- and the query parameter can be assigned to a route. Until Angular 2, route parameters were stored in a key-value object and were accessible through standard JavaScript syntax. Do you want to succeed in your Angular 4 Interview Questions and Answers? Read on!

Another unique feature is that the functions that were necessary for animations are placed in their package. This has been done to avoid creating unnecessary bundles of significant size. Until Angular 2, these functions were offered as part of the core module and were always included even if they were not getting used in apps.

In angular 4, the use of decorators is done extensively for compiling the code. There are four types of decorators – Class, Property, Method, and Parameter.

Type security and speed ngc-Compilerhave improved in Angular 4 as compared to Angular 2. If you are scrolling on the web for angular 4 interview questions and answers pdf, then this guide will gonna help you.

Reviewed and verified by Umesh Singh
Umesh Singh

My name is Umesh Singh having 11+ experience in Node.JS, React JS, Angular JS, Next JS, PHP, Laravel, WordPress, MySQL, Oracle, JavaScript, HTML and CSS etc. I have worked on around 30+ projects. I lo...