Top Angularjs Interview Questions 2020: UPDATED

Angularjs Interview Questions

Top Angularjs Interview Questions 2020: In this article, I am going to list some of the most key Angular Interview Questions and Answers which will set you apart in the interview process in 2020.

Angular continues to rule the arena of the JavaScript framework and has shown itself to be a worthy investment for web developers who pursue to fast-track their profession.

No wonders there, Angular is known for its facility to develop single-page web applications that encompass three serious components: agility, speed and a strong community backing it up.

Angularjs Interview Questions 2020

Let us commence by taking a look at some of the most frequently asked Angularjs interview questions.

#1 Who created Angular JS?

Firstly it was created by Misko Hevery and Adam Abrons. Presently it is being developed by Google.

#2 What are the key features of AngularJS?

Some key features of AngularJS are given below:

MVC- In AngularJS, you just have to divide your application code into MVC modules, i.e., Model, Directive, Template, Routing, View, and the Controller.

#3 What is services in AngularJS?

AngularJS services are the singleton objects or functions which are second-hand for carrying out definite tasks. It holds some corporate ideas and these drives can be called as a directive, controllers, and filters and so on.

Some of the imperative services used in any AngularJS application are as follows:

$http, $window, $Location, $timeout, $Log, $sanitize, $Rootscope, $Route and more.

#4 Explain what are directives?

A directive is rough that present’s new syntax, they are like markers on DOM element which attaches a superior behaviour to that DOM element. In AngularJS application, directives are the most significant components. In AngularJSthere are many in-built directives such as “ng-app“, “ng-model“, “ng-init“,”ng-bind“, “ng-repeat” etc.All AngularJS directives start with the word “ng“.

#5 What are the advantages of using AngularJS?

This question is most asking Angularjs Interview Questions in 2020, “What are the advantages of using AngularJS?” AngularJS has several advantages in web development.

  • AngularJS cares MVC pattern
  • Can ensure two ways data binding using AngularJS
  • Angular has pre-defined form validations
  • Angular supports both client-server communication
  • Angular supports animations

#6 What Angular JS routes do?

Routing is one of the key features of the AngularJS framework, which is beneficial for creating a single page application (also referred to as SPA) with multiple views.

It routes the application to different pages deprived of reloading the application. In Angular, the ngRoute module is used to implement Routing. The ngView, $routeProvider, $route, and $routeParams are the different components of the ngRoute module, which assist for configuring and mapping URL to views.

#7 What is data binding in AngularJS?

One more Angularjs Interview Questions in 2020, Data binding is the automatic synchronization of data between view and model. In AngularJS, it achieves the automatic synchronization process between the model and view.

If the model is changed, the view reflects it automatically and vice-versa. There are two ways of data binding that AngularJS ropes:

  • One Way Data Binding
  • Two Way Data Binding

#8 What is string interpolation in Angular.js?

In Angular.js the compiler through the compilation process matches attributes and text using interpolate service to see if they contain embedded expressions.

As a portion of normal digest cycle, these expressions are updated and registered as watches.

#9 What is injector?

An injector is a service locator. The injector is used to retrieve object instances as defined by the provider, invoke methods, instantiate types and load modules. There is a single injector per AngularJS application, it aids to lookup an object instance by its name.

#10 What is the difference between a link and compile in Angular.js?

  • Compile function is used for template DOM Manipulation and to gather all the directives.
  • In Angular, Link is used for registering DOM listeners as well as for instance DOM manipulation and is executed once the template has been copied.

#11 Why we use Angularjs

  • AngularJS is based on MVC pattern; it aids us to organize our web apps or web application properly.
  • AngularJS aids to make responsive and well-organized web apps that are more expansive and readable.
  • AngularJScharts two-way data binding. Two-way data binding helps us so that any changes in the model will be updated view and vice-versa without any operation on DOM or events.
  • AngularJS cares to make your own directive that makes reusable components to be used according to your needs. It is also abstract DOM manipulation logic.
  • It supports services and dependency injection which we can easily inject in our controller and provides some utility code as per our needs.

#12 How did you use Angularjs?

With AngularJS, web designers can use HTML as the template language and it allows for the extension of HTML’s syntax to convey the application’s components effortlessly.

As we know AngularJS is a structural framework for dynamic web applications. Angular makes much of the code you would otherwise have to write totally redundant.

Regardless of the fact that AngularJS is commonly related to SPA, you can use Angular to build any kind of app, taking advantage of features like Templating, Two-way binding, RESTfulAPI handling, AJAX handling, modularization, dependency injection, etc.

#13 How to create a directive in Angularjs?

And the 13 number of Angularjs Interview Questions in 2020 is “How to create a directive in AngularJs App?” Most of you have seen the basic directives that we use in everyday application development.

They are ng-model, ng-app, and ng-init, ng-repeat. AngularJS allows you to Create Controller & Services for an application.

Similarly, we can also create Directives in AngularJS.

Basic Way:

In AngularJS, Directives starts with ng- or data-ng-. And there are various ways we can create directives in AngularJS:

Another way:

It’s quite similar to HTML where we store custom data that will be stored in a page or an application. You can also validate the same through HTML editor.

Sample Code:

DirApp.directive('myCustomDir', function () { return {
template: "<p>{{result}}</p>"
}
});

#14 Why Reactjs popularity than Angularjs

Angular is a software design pattern that benefits in making components reusable, testable and maintainable.AngularJS bids low performance with complex and dynamic applications.

Also, virtual DOM enables the faster performance of ReactJS apps than AngularJS apps for the applications of the same size.

#15 What is scope in Angularjs?

Scope in Angular is an object that states to the application model. It is an execution context for expressions. Scopes are decided in a hierarchical structure which mimics the DOM structure of the application. Scopes can lookout expressions and propagate events.

#16 What are the interview questions on model and controller in Angularjs?

AngularJS – Controllers. AngularJS application mostly relies on controllers to control the flow of data in the application. A controller is defined using the ng-controller directive. A controller is a JavaScript object that contains attributes/properties, and functions.

Model − It is the lowest level of the pattern responsible for maintaining data. View − It is responsible for displaying all or a portion of the data to the user.

#17 How to refer the parent to child component Angularjs

Communicating Events from Parent to Child in AngularJS Components.

Pass data from parent to child with input binding HeroChildComponent has two input properties, typically adorned with @Input decorations.

import { Component, Input } from '@angular/core'; import { Hero } from './hero';
@Component({
selector: 'app-hero-child', template: `
<h3>{{hero.name}} says:</h3>
<p>I, {{hero.name}}, am at your service, {{masterName}}.</p>
`
})
export class HeroChildComponent { @Input() hero: Hero; @Input('master') masterName: string;
}

The second @Input aliases the child component property name masterName as ‘master’.

The HeroParentComponent nests the child HeroChildComponent inside an *ngFor repeater, binding its master string property to the child’s master alias, and each iteration’s hero instance to the child’s hero property.

import { Component } from '@angular/core'; import { HEROES } from './hero';
@Component({
selector: 'app-hero-parent', template: `
<h2>{{master}} controls {{heroes.length}} heroes</h2>
<app-hero-child *ngFor="let hero of heroes" [hero]="hero"
[master]="master">
</app-hero-child>
`
})
export class HeroParentComponent { heroes = HEROES;
master = 'Master';
}

#18 How to do form validation in Angularjs

If you’re preparing for Angularjs Interview then this is the most asking Angularjs Interview Questions in 2020, AngularJS provides client-side form validation and enriches form filling and validation. It checks the state of the form and input fields (input, text-area, select), and notify the user about the current state.

It also holds the info about whether the input fields have been touched, or modified, or not.

There are following directives that can be used to track error:

$dirty - It states that the value has been changed.
$invalid - It states that the value which is entered is invalid.
$error - It states the exact error.

Moreover, we can use no validate with a form declaration to disable the browser’s native form validation.

#19 How to apply a filter in Angularjs?

One more Angularjs Interview Questions, Filters format the value of an appearance for a display to the user. Filters are used to modify the data. They can be clubbed in expression or directives using pipe (|) character.

AngularJS comes with a group of built-in filters, but it is easy to define your own as well. They can be castoff in view templates, controllers or services.

The underlying API is the $filterProvider.

#20 What is a single page application in Angularjs?

Single Page Application is a web application that turns on a single page. All your code (HTML, CSS, and JS) is retrieved with a single page load. And navigation between pages performed deprived of refreshing the whole page.

Final words

So this carries us to the end of this article. The topics that you learned in this Angular Interview Questions are the most sought-after skill sets that recruiters look for in an Angular career.

These set of Angular Interview Questions will absolutely benefit you ace your job interview. Good luck with your interview!

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