AngularJS Interview Questions and Answers

How to validate form data in AngularJS?

AngularJS has enriches client-side form filling validation. It support HTML 5 validations and also allow to creationof custom validation to validate data.
For example following can be used to track error: 
•    $dirty - states that value has been changed.
•    $invalid- states that value entered is invalid.
•    $touched-states that value has been touched.

Explain the concept of Watchers, Dirty checking and Digest cycle?

The data-bindings in AngularJS can be achieved via Watchers, Dirty checking and Digest cycle concept-
Watchers: Angular creates a watcher that observes the view property, which will be triggered whenever the model changes, allowing Angular to update the view content.
Dirty checking: It is the process to check whether the item has been changed or not by comparing a value with its previous value, and if it has changed then a change event is fired.
Digest cycle: when any change happens in the model the view gets updated. This updating of the model and the view is done by a loop called as digest cycle.

What is dependency injection and how does it work in Angular?

Dependency injection is a software design pattern where we inject the dependent objects rather than consumer creating the objects. 
There are two big benefits of DI: - Decoupling and Testing.

How to make an Ajax call using AngularJS?

AngularJS provides $http control which works as a service to make ajax call to read data from the server. The server makes a database call to get the desired records. AngularJS needs data in JSON format. Once the data is ready, $http can be used to get the data from server in the following manner:
functionajaxController($scope,$http) {
$http.get(url).success( function(response) {
   $scope.showdataonPage = response; 

How do we make HTTP get and post calls in Angular?

To make HTTP calls we need to use the “$http” service of Angular. In order to use the http services you need to make provide the “$http” as an input in your function parameters as shown in the below code.
$http({ method: "GET", url: "http://localhost/SomeMethod"     }).success(function (data, status, headers, config)
        {                   // Here goes code after success        }
$http({ method: "POST", url: "http://localhost/SomeMethod "}).success(function (data, status, headers, config)
    {      // Here goes code after success    }

Explain ng-app directive?

The ng-app directive is used to bootstrap an AngularJS application.It can also be used to declare module for an application and for initialize the angular expression variable.

Explain ng-controller directive?

The ng-controller directive specifies a Controller thatbind with scope to populate view from model data.

Explain ng-model directive?

The ng-model bind the view property by evaluating the expression on the current scope. If the property doesn't already exist on this scope, it will be created implicitly and added to the scope.
The two way binding can enable on property with this directive.

Explain ng-click directive?

The ng-Click directive allows you to specify custom behavior and evaluation of expression when an element is clicked.
For ex;value of count changed when html button are clicked 
<button ng-click="count = count + 1" ng-init="count = 0">Increment</button>
count: {{count}}

Explain ng-repeat directive?

The ng-Repeat directive will repeat the instance of the element upon which it is declared for each item in a collection.

There are following variable we can used with this directive
$index : Iterator offset of the repeated element (0..length-1)
$first : True, if the repeated element is first in the iterator
$middle : True, if the repeated element is between first and last in the iterator
$last : True, if the repeated element is last in the iterator
$even : True, if the iterator position $index is even (otherwise, false)
$odd : True, if the iterator position $index is odd (otherwise, false)

Explain ng-show and ng-hide directive?

The ng-Show directive shows or hides the given HTML element based on the expression provided to the ng-Show attribute. And samethe ng-Hide directive shows or hides the given HTML element based on the expression provided to the ng-Hide attribute.

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Atmospheric pressure at sea level equals ?

General Knowledge of India

Which of the following dance forms was introduced by the great Vaishnava saint and reformer Mahapurusha Sankaradeva ?

Which of the following is the only classical dance of india having links with Muslim culture and represents a unique synthesis of Hindu and Muslim genius in art ?

Time and Distance

Starting from the same point at the same time, Ruhan and Yuvan had to reach the same destination. While Ruhan drove at 45 km/hr, Yuvan was slower by 5 km/hr. If Yuvan arrived at the destination an hour after Ruhan did, the distance covered by each, in Kilometres, was ?

Simple Interest

A sum of money was invested at a certain rate of simple interest for 4 years. Had the sum been invested at a rate 3% higher than the actual rate, the interest earned would have been 720 Rs more. Find the sum initially invested?

Ratio and Proportion

A bag contains red, blue and black balls. The ratio of red to blue balls is 3 : 5. The ratio of black to red balls is 3 : 4. What is the ratio of blue to black balls?

Profit and Loss

Selling a pack of incense sticks for 136 Rs resulted in a loss of 15%. To make a profit of 10%, the selling price should be ?


23% of a bucket full of diluted milk was water. If the quantity of pure milk in the bucket was 15.4 liter, then the capacity of the bucket was ?


The average of the marks obtained by three girls in a test was twice the average of the marks obtained by eight boys in that test. If the total marks obtained by all these examinees was 168, find the average marks each of the girls obtained ?

Pipes and Cistern

44 pipes can fill a large water tank in 27 hours. How many hours it take for 66 pipes to fill four such tanks ?


A natural number, when divided by 3, 4, 5, 6, and 7 respectively, leaves corresponding remainder of 2, 3, 4, 5 and 6. What is the smallest of all such numbers fulfilling the above condition ?


If in a certain code language, PRINT is written as 34825 and TRUE is written as 5479. Then, how will TENURE be written in that language?

Order Sequence

Arrange the given words from smallest to biggest-

Statement and Conclusion

All socks are shoes
Some shoes are black

I. Some shoes are socks.
II. No scoks is black


The difference between the place value of 4 and 2 in the number 833749502 is ?


GIKM : HJLN :: PRTV : .........?

Order Sequence

In a row of girls, Nanda is eighth from the left and Chanda is nineteenth from right. When Nanda and Chanda interchange their positions, Chanda becomes twnty-third form right. How many girls are there in the row?


Summer: Day :: Winter : ........?