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AngularJS Interview Questions & Answers

For dynamic web apps, AngularJS is a structural framework. HTML is allowed to use as the template language and it allows extending HTML's syntax to express the application's components clearly. The data binding and dependency in AngularJS remove the code without having to write the code. All these happen within the browser, making Angular JS an ideal partner with any server technology. The impedance mismatch between dynamic applications and static documents is often solved with:

A library: a collection of functions used while writing web apps.
Frameworks: a particular type of implementation of a web application, where the code fills in the details.

Due to the multifaceted features of AngularJS, many companies are using it to sin apps for their own systems or to deliver worthy software to its clients. In any case, they need a very skilled person who knows the complete AngularJS framework to fill these job roles. If you are someone who is likely to attend or conduct an interview based on AngularJS, then please go through a list of questions which have been dealt with in this blog.

AngularJS Interview Questions and Answers is Classified into Four Parts:

These are the most popular questions that have been doing the rounds in many AngularJS interview sessions.

AngualrJS Interview Questions

AngularJS Interview Questions and Answers

For anyone who is looking forward to attending an interview based on AngularJS recently, here are the most popular interview questions and answers to help you in the right way for your job interview. After taking inputs from various students who have appeared in AngularJS interviews lately we have compiled a list of the most frequently asked questions along with their appropriate answers to help the fresher and the experienced individuals.

AngularJS Interview Questions Fresher

Q1). What are the key differences between JQuery and AngularJS?

Jquery is a library utilized for DOM control whereas Angular is a structure. ... Jquery does not have two-way restricting highlights while Angular has key highlights like routing, orders, two-way information authoritative, models, reliance infusion, unit tests and so on.

Q2). What is AngularJS?

AngularJS is a framework used for creating single web page applications in JavaScript. It allows using HTML as the template language that enables to extend HTML’s syntax to express the components of the application clearly.

Q3). What are the advantages of using an Angular.js framework?

Angular.js framework comes with the following advantages:

Supports MVC design
Supports two-way data binding
Support static layout and precise formats
Can include a custom mandate
Supports REST full administrations
Supports shape approvals
Support both customer and server correspondence
Support reliance infusion
Applying Animations
Event Handlers

Q4). Who created AngularJS?

Initially, Angular JS was developed by Misko Hevery and Adam Abrons and later on it was further developed by Google.

Q5). Explain what are the key features of AngularJS?

The key features of AngularJS are-

Scope
Controller
View
Model
Services
Data Binding
Directives
Testable
Filters

Q6). What is the architecture of AngularJS?

The architecture of AngularJS is based on 3 components. They are

The Template (View)
The Controller (Controller)
The Scope (Model)

Q7). Explain what is scope in AngularJS?

The application model is referred to as scope, which acts between the application controller and the view, in order to connect them. Scopes can watch expressions and propagate events and are arranged in the hierarchical structure which can also impersonate the Document Object Model(DOM) structure of the application.

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Q8). What are the typical characteristics of a ‘Scope’?

The scope is an AngularJS object that refers to the model of the application. It is an execution setting for articulations. Scopes are usually arranged in progressive structures which emulate the DOM structure of the application. Scopes can watch articulations and proliferate events. The attributes of Scope are:

Scopes give APIs ($watch) to watch display transformations.
Scopes give APIs ($apply) to spread any model changes through the framework into the view from outside of the "Angular Realm" (controllers, administrations, Angular occasion handlers).
Scopes can be settled to restrain access to the properties of utilization segments while giving access to shared model properties. Settled scopes are either "child scopes" or "isolate extensions". A "child scope" (prototypically) acquires properties from its parent scope. An "isolate scope" does not.
Scopes gives the setting against which articulations are assessed. For instance, {{username}} expression is trivial, except if it is assessed against a particular degree which characterizes the username property.

Q9). Explain a Template in AngularJS?

The template in AngularJS is the HTML part of the angular app. It is similar to a static HTML page, apart from the fact that templates do contain additional syntaxes which then allow the data to be inserted in it in a directive to provide a tailored user experience.

Q10). How will you explain data binding concept in AngularJS?

As indicated by AngularJS.org, “Data-binding in Angular apps is the automatic synchronization of data between the model and view components. The way that Angular implements data-binding lets you treat the model as the single-source-of-truth in your application. The view is a projection of the model at all times. When the model changes, the view reflects the change and vice versa.”

There are two different ways of data binding they are-

Data mining in traditional format frameworks
Data binding in angular templates

AngularJS Interview Questions Experienced

Q11). Explain what are directives? Mention some of the most commonly used directives in AngularJS application?

Anything that introduces new syntax, are called directives. They are like markers on the Document Object Model(DOM) element that incorporates a special behavior to it. Directives are the most important components in AngularJS application. Some of the commonly used directives are ng-model, ng-bind, ng-repeat ng-App, ng-show etc.

Q12). Explain the concept of a Controller in AngularJS?

The controller is a function in AngularJS which usually tries to take an empty scope object as its parameter and then adds the fields to it. This enables the functions to be later exposed to the user via the view component.

Q13). Explain what are services in AngularJS?

The services in AngularJS are the singleton objects or functions, used for carrying out specific tasks. Angular JS holds business logic and these functions are known as controllers, directive, and filters and so on.

Q14). What is the link function and how is it different from a compile?

The link function is the feature that combines the directives with a scope in an AngularJS environment to produce a live view. It is different from a compile because the function of a compile is template DOM manipulation along with the collection of all the directives present.

Q15). Is AngularJS a framework, library or a plugin?

AngularJS is an open-source client-side MVC framework for creating dynamic web applications.

Q16). What is string interpolation in AngularJS?

Using interpolate service, the compiler matches the text and attributes in the compilation process in order to check the embedded expressions. These expressions are updated and registered as watches, as a part of the normal digest cycle.

Q17). Explain what is the injector?

An injector is a service locator as defined by a provider, instantiate types, invoke methods and load modules. The injector is used to retrieve object instances. The single injector present per Angular application helps to look up an object instance by its name.

Q18). Explain what is a factory method in AngularJS?

The factory method is used for creating the directive. When compiler matches the directive for the first time, the factory method is invoked once. The factory method is invoked using $injector.invoke.

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Q19). What are Controllers in AngularJS?

Controllers are JavaScript capacities which give information and rationale to HTML UI. As the name recommends, they control how information streams from the server to HTML UI.

Q20). What is an Angular Expression?

In an AngularJS environment, an Expression is a typical JavaScript that resembles the code snippets which are used to bind the expression data in the view or the HTML. Every Angular expression needs to be written the two curly braces as given below- {{a+b}}

AngularJS Coding Interview Questions

Q21). Explain the digest cycle in AngularJS digest cycle?

A digest cycle in AngularJS is the process behind data binding in AngularJS environment. The digest cycle is generally triggered automatically but if you want to trigger it manually then you can use $apply() command.

Q22). What is dirty checking in AngularJS?

Whenever a digest cycle is going on, all the new scope model values are matched against the previous scope values. This is called dirty checking.

Q23). What do you need to change as a developer when you are migrating from AngularJS 1.4 to AngularJS 1.5 version?

There is a very minor change that you would have to do and that is you would need to change the .directive command to .component command

Q24). What are the basic steps for setting up an Angular app?

Setting up an angular app is not difficult at all. You just have to follow the steps given here-

First of all, create an angular.module
Then assign a controller to the module that you have created
Thereafter link this module to HTML with the help of ng-app
Lastly, link your controller to the HTML with the ng-controller directive in the app

Q25). Explain the concept of scope hierarchy? How many scopes can an application have?

Each angular application consists of a root scope but can have several child scopes. The application can have multiple scopes as child controllers and directives create new child scopes. When new scopes are created they are added as children of their parent scope, they also create a hierarchical structure similar to DOM.

Q26). Explain what is the difference between AngularJS and backbone.js?

AngularJS combines the functionalities of most of the third party libraries and supports individual functionalities that are required to develop HTML5 Apps.

js acts individually.

Q27). How to make an ajax call using Angular JS?

To make ajax call, AngularJS provides ‘$http’ control which provides the service to read data from the server. A database call initiates the server to fetch the desired records. Once the data is ready, $http can be used to get the data from the server in the following manner:

functionstudentController($scope,$http){ 
varurl="data.txt"; 
$http.get(url).success(function(response){ 
$scope.students= response; 
}); 
}

Q28). What is the use of $routeProvider in AngularJS? What is $rootScope?

$routeProvider is the key service which sets the configuration of URLs, attaches a controller with the same and maps them to the corresponding HTML page or ng-template,

The scope is a special JavaScript object, that contains the model data. The role of joining the controller with the views is done by scope. Model data is accessed via $scope object In controllers. $rootScope is the parent of all of the scope variables.

Q29). How to add routing?

var app = angular.module("AngularApp", ['ngRoute']);  
app.config(['$routeProvider',  
function($routeProvider)  
{  
$routeProvider.  
when('/page1',   
{  
templateUrl: 'Modules/Page1/page1.html',  
controller: 'Page1Controller'  
})  
.  
when('/page2',   
{  
templateUrl: 'Modules/Page2/page2.html',  
controller: 'Page2Controller'  
})  
.  
otherwise  
({  
redirectTo: '/page1'  
});  
}  
]);

Q30). What is linking function and what are the types of linking function?

Link combines the directives with a scope and produces a live view. Link function is responsible for registering DOM listeners as well as updating the DOM. It is executed after the template is cloned.

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Pre-linking function:Pre-linking function is executed before the child elements are linked. For DOM transformation, It is not considered as the safe way.
Post linking function:Post linking function is executed after the child elements are linked. It is safe to do DOM transformation by post-linking function.

AngularJS Tricky Interview Questions

Q31). What is DI (Dependency Injection) and how an object or function can get a hold of its dependencies?

DI or Dependency Injection is a software design pattern that deals with how code gets hold of its dependencies. In order to retrieve elements of the application, the operation “config” uses dependency injection which is required to be configured when the module gets loaded.

The ways that object used to hold of its dependencies are:

Typically, dependency can be created using the new operator.
Dependency can be looked up, by referring to a global variable.
Dependency can be passed to where it is required.

Q32). Explain what is Angular Expression? Explain what is the key difference between angular expressions and JavaScript expressions?

Angular expressions are code snippets that are usually placed in the binding as in Javascript. {{expression}} The key difference between the JavaScript expressions and Angular expressions

Context: Angular, the evaluation of expressions are done against a scope object, while in the Javascript, the evaluation of expressions is done against the global window
Forgiving: In the Angular expression, evaluation is done by forgiving to null and undefined, whereas in Javascript undefined properties generates TypeError or ReferenceError. No Control Flow Statements: in an angular expression Loops, conditionals or exceptions cannot be used
Filters: one can use filters to format data before displaying it

Q33). Can we have nested controllers in AngularJS?

Yes. We can create nested controllers in AngularJS. The nested controller is defined in a hierarchical manner while using in View. Take a look at below code. hierarchy is "MainCtrl -<

SubCtrl -&amp;amp;lt; SubCtrl1".

&amp;amp;lt;div ng-controller="MainCtrl"&amp;amp;gt;
{{message}} {{name}}!

&amp;amp;lt;div ng-controller="SubCtrl"&amp;amp;gt;
Hello {{name}}!

&amp;amp;lt;div ng-controller="SubCtrl2″&amp;amp;gt;
{{message}} {{name}}! Your username is {{username}}.
&amp;amp;lt;/div&amp;amp;gt;

&amp;amp;lt;/div&amp;amp;gt;

&amp;amp;lt;/div&amp;amp;gt;

Q34). Do you think AngularJS compatible with all the browsers?

Yes, AngularJS is pretty much compatible with most of the browsers. To name a few compatible browsers Safari, Chrome, Firefox, Opera 15, IE9.

Q35). How will you execute a routing in the AngularJS framework?

It is a very easy five-step process as follows:

The first step would be to add the “Angular-route.js” file to your view.
The second step would be to inject “ngroute” functionality when you are creating an Angular app object.
In the next step, you are required to configure your route provider.
Thereafter comes the step where you need to define the hyperlinks.
Lastly, define the sections where you have to load the view.

Q36). Is it true that Angular utilizes the jQuery library?

Truly, Angular can utilize jQuery if it's present in the application when the application is being bootstrapped. In the event that jQuery is absent in the script path, Angular falls back to its very own usage of the subset of jQuery that we call jQLite.

Q37). List down the types of the component on which we can create custom directives.

AngularJS offers help to make custom directives for the accompanying:

Element directives − Directive enacts when a coordinating component is experienced.
Attribute − Directive initiates when a coordinating characteristic is experienced.
CSS − Directive enacts when a coordinating CSS style is experienced.
Comment − Directive enacts when a coordinating comment is experienced.

Q38). Explain bootstrapping in AngularJS?

Bootstrapping in AngularJS refers to the process of instating, or beginning the Angular application. AngularJS bolsters programmed and manual bootstrapping.

Automatic Bootstrapping: this is finished by adding ng-application directive to the base of the application, regularly on the tag or the tag on the off chance that you need angular to bootstrap your application consequently. At the point when angularJS discovers ng-application mandate, it stacks the module related with it and after that assembles the DOM.
Manual Bootstrapping: Manual bootstrapping gives you more control over how and when to introduce your angular App. It is valuable where you need to play out some other activity before Angular kicks in and arrange the page.

Q39). How will you explain the SPA (Single Page Application)? How can you execute an SPA with Angular?

Single Page Applications (SPAs) are web applications that heap a solitary HTML page and progressively refresh that page as the client collaborates with the application. In an SPA the page never reloads, however parts of the page may invigorate. It's where we make a solitary shell page or ace page and load the website pages inside that ace page as opposed to stacking pages from the server by doing postbacks. We can actualize SPA with Angular utilizing Angular routes.

Q40). What is Jasmine tool?

Jasmine is a conduct driven improvement tool for JavaScript that has turned into the most mainstream decision for testing AngularJS applications. Jasmine gives capacities to help organizing your tests and furthermore making statements. As your tests develop, keeping them very much organized and recorded is fundamental, and Jasmine accomplishes this.

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