Angularjs Interview Questions and Answers
A JavaScript client-side framework, AngularJS offers a structured method of building websites and applications. It is a structural framework which is used to develop the dynamic web app. We have an impressive collection of AngularJS Interview Questions that is a must-read for all developers and designers!. Its JavaScript library enforces the Model View Controller (MVC) framework. AngularJS I said to be one of the most widely used JavaScript client-side frameworks in the world.
| Quick Facts About AngularJS | |
|---|---|
| What is the latest version of Angular? | Angular 11.0 released on 11th November 2020 |
| When did angular release? | 4th May 2018 |
| When was Angular first released? | Angular 2.0 and released on 14th September 2016 |
| What language does Angular use? | TypeScript |
Our angular questions has been created by seasoned Angular experts. It shall help you to answer some of the most frequently asked questions during an job interview.
Most Frequently Asked Angularjs Interview Questions
Most of the Javascript frameworks parse the HTML template as a stream and return the result as a string. The resulting string gets dumped into the DOM and can be retrieved using innerHTML(). AngularJS works directly on HTML DOM rather than strings. It uses two-way data binding to sync the data.
Services are one of the ways to communicate with controllers, but it is possible to inject one service into another. Services can be used for doing other things like authentication and logging.
Directives are for creating widgets or wrapping things like jquery plugins. However, if you do not need two-way data binding, then you do not need to wrap them.
| Service | Factory |
|---|---|
| Creates a service object in Angular by using the "new" keyword. | In Angular, factories are the most popular way to create and configure a service. |
| It does not use a type-friendly injection mode. | It uses a type-friendly injection mode. |
| It cannot create primitives. | Factory can be used to build primitives. |
| It is configurable. | It is not configurable. |
Example of a Factory in Angular
app.controller('myFactoryCtrl', function ($scope, myFactory) {
$scope.artist = myFactory.getArtist()
})
app.factory('myFactory', function () {
var _artist = '';
var service = {}
service.getArtist = function () {
return _artist
}
return service;
})
Example of a Service in Angular
app.controller('myServiceCtrl', function ($scope, myService) {
$scope.artist = myService.getArtist();
});
app.service('myService', function () {
var _artist = '';
this.getArtist = function () {
return _artist;
}
});
It is a mechanism that makes an application as a Single Page Application. It routes the application to different pages without reloading the whole application.
getCheckDimenstions(ev: Event) {
if (ev && ev.target && ev.target.files) {
const file = ev.target.files[0];
const img = new Image();
img.onload = function() {
alert('Width:' + this.width + ' Height: ' + this.height);
};
img.src = URL.createObjectURL(file);
}
}
Directives are a core feature of AngularJS that allows you to discover new HTML syntax, which is specific to your particular application. Directives are functions that execute when the Angular compiler finds them in DOM. The different types of directives are an element, attribute, CSS class, and comment.
An injector is a service locator that is used to retrieve the object instances as defined by the invoke methods, provider, load modules, and instantiate types.
Note: Our aim while creating angular interview questions and answers, is to help you grow as an Angular Developer. The questions mentioned here have been asked by leading organizations during technical rounds of the interview process.
var $injector = angular.injector();
expect($injector.get('$injector')).toBe($injector);
expect($injector.invoke(function($injector) {
return $injector;
})).toBe($injector);
The factory method, used for creating a directive, gets invoked when the compiler matches the directive for the first time. This function can be invoked by $injector.invoke.
Syntax: module.factory( 'factoryName', function );
When you declare factoryName as an injectable argument, you will get the value which will be returned by invoking the function reference passed to the module.factory.
Yes, Angular uses jQuery if it is present in the app when your application is being bootstrapped. However, if jQuery is not present in the script path, Angular will fall back to its own implementation of the subset of jQuery. This is called jQLite.
In Angular, the scope is the binding part between the HTML, i.e. the view and the Javascript, urf, controller. It acts like an object having various available properties and methods. The scope is available for both modes, view and controller. Here’s an example of how to use the scope in Angularjs properly:
<div ng-app="myApp" ng-controller="myCtrl">
<h1>{{carname}}</h1>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.carname = "Volvo";
});
</script>
Development History of Angular JS
AngularJS was developed by Misko Hevery and Adam Abrons in 2009. The framework is maintained by Google now.
It is not a single piece in the overall puzzle of building the client-side of a web application. It also handles all of the AJAX and DOM code you once wrote by hand and puts it in a clear structure.
Advantages of AngularJS
- Easy to implement MVC.
- Makes HTML more intuitive and easier to maintain.
- More comfortable to access, manipulate, and implement.
- Applications use very less code compared to other JavaScript applications.
- Supports the test-driven development approach (TDD)
Though every interview is different, we can help you crack your next interview with the most commonly asked Angularjs Interview Questions, which will help you achieve success.
Installation Steps
- Open the link https://angularjs.org/
- You will see two options on this page - View on GitHub and Download.
- Click the download button, and it will start downloading angular.min.js.
- Create an HTML page and include the following AngularJS JavaScript file
http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js with script tag - Run the HTML page in the browser.