26 ANGULARJS INTERVIEW QUESTIONS AND ANSWERS FOR 2019 - PREPARED BY DEVTEAM.SPACE
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26 AngularJS Interview
Questions and Answers for 2019
Prepared by DevTeam.Space
DevTeam.Space is a data-driven agile
software development platform
Successful businesses and entrepreneurs
rely on DevTeam.Space for their most
innovative projects
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© DevTeam.Space. Confidential and proprietaryWhether you’re an entrepreneur, a project manager in a large enterprise, or a CTO, you are well
aware that the success of your project rests on your ability to find top developers.
This guide focuses on the original AngularJS JavaScript framework. If you’re looking for questions
on the Angular 2, 4, 5, 6 or 7 (simply referred to as “Angular), click here:
● Angular Interview Questions and Answers
AngularJS developers are mostly needed to support the many existing applications that use the
original AngularJS framework. Here, we go through the interview process and questions you need
to reliably identify the best candidates to support your AngularJS application.
First Things First: Select Your Job Requirements
AngularJS is a powerful and flexible framework that can be applied in many different ways. You
need developers with the right skill and experience for your AngularJS project. To do that, you need
to take a hard look at the demands of your AngularJS web app to figure out your unique job
requirements.
Some example requirements include:
● Essential web development skills – E.g. HTML, Javascript
● AngularJS-specific skills – E.g. Modules you use on your applications
● Library/toolkit experience – E.g. Jasmine and Karma
● Design skills – Performance optimization, building scalable applications
● Communication skills – Discussing problems and constraints with clients
● Being a self-starter – If they’ll have to figure out solutions by themselves
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© DevTeam.Space. Confidential and proprietaryAvoid making a laundry list of non-essential skills for your perfect AngularJS developer. Instead,
focus on what your candidate will really be doing day-to-day. Keep your requirements’ list as short
as possible. Cut anything they can do without or learn on the job.
With clearly stated requirements, you’ll be able to choose the right AngularJS coding interview
questions and have a much better idea of what kinds of responses you are looking for.
The questions in this guide are broken down into two sections: Basic Interview Questions and
Advanced Interview Questions. You should use the basic AngularJS programming interview
questions in this section if you’re looking for a junior or entry level developer with less
experience.
Skip to the Advanced developer sections for AngularJS interview questions and answers for
experienced developers).
AngularJS Basic Interview Questions
A Junior developer is someone just starting their career with less than 2 years of experience. Junior
developers are usually hired as part of a team, as they need close guidance from more experienced
AngularJS developers. Their main job is to execute tasks given to them, which are then
cross-checked.
Skill Requirements for Junior Java Developers
● Basic HTML, CSS and Javascript skills
● Foundational AngularJS knowledge
● Learning on the job
● Following instructions and receiving feedback
● Thinking like a programmer
Example AngularJS Basic Interview Questions and Answers
Note: Important keywords are underlined in the answers. Bonus points if the candidate mentions
them!
Question 1: Briefly explain the CSS box model. Write some code snippets to describe what you
mean.
Requirement: Basic CSS skills
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© DevTeam.Space. Confidential and proprietaryAnswer: The CSS box model refers to the layout and design of HTML elements. It’s a box shape that
wraps around each HTML element. A box is made up of its content, padding, border and margin.
● Content of the box
● Padding
● Border
● Margin
(the same padding on all 4 sides)
padding: 25px;
(padding for the top, right, bottom, left)
padding: 25px 50px 75px 100px;
(top/bottom padding 25 pixels, right/left padding 50 pixels)
padding: 25px 50px;
For example:
Page Title
Interview Example Web Page
Some content goes here
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© DevTeam.Space. Confidential and proprietaryQuestion 2: Explain what a Javascript callback function is and provide a simple example.
Requirement: Basic Javascript skills
Answer: A callback function is a function that is called after another function has finished executing.
A callback function is passed to another function as an argument and is invoked after some
operation has been completed. For example:
function modifyArray(arr, callback) {
arr.push(100);
callback();
}
var arr = [1, 2, 3, 4, 5];
modifyArray(arr, function() {
console.log("array has been modified", arr);
});
Question 3: Briefly describe AngularJS in one or two sentences.
Requirement: Foundational AngularJS knowledge
Answer: AngularJS is an open-source Javascript framework. It is designed for building dynamic
single page applications that require less coding than doing everything yourself in Javascript.
Question 4: What is a Single Page Application? How do they work in AngularJS
Requirement: Foundational AngularJS knowledge
ingle Page Applications (SPAs) are web applications that use only one HTML page. As the
Answer: S
user interacts with the page, new content is dynamically updated on that master page. Navigation
between pages happens without refreshing the whole page. AngularJS uses AJAX and to
dynamically update HTML elements. Angular Routing can be used to make SPAs. The result is an
application that feels more like a desktop app rather than a webpage.
Question 5: What are some of the key features of AngularJS?
Requirement: Foundational AngularJS knowledge
Answer: The more of these features that candidates can name the better:
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© DevTeam.Space. Confidential and proprietary● Scope
● Controller
● Model
● View
● Services
● Data Binding
● Directives
● Filters
● Testable
Question 6: Explain the basic steps of setting up an Angular app?
Requirement: Foundational AngularJS knowledge
Answer: Basic steps:
● Create an angular.module
● Assign a controller to the module
● Link your module to HTML with ng-app
● Link the controller to HTML with ng-controller directive
Question 7: What is scope in AngularJS?
Requirement: Foundational AngularJS knowledge
Answer: Scope is a Javascript object that joins the controller (the Javascript application logic) and
the views (the HTML). It represents the model part of an AngularJS Model-view-controller
application. The controller sets the member variables or properties in the scope and the view binds
to them.
Question 8: How would you learn about a new Javascript library?
Requirement: Learning on the job
Answer: Web development is changing all the time, and developers need to be able to learn
constantly. Here you are finding out how the candidate approaches the learning process. You want
to see that they have an idea of what information they will need and where to find it. For Javascript
libraries, that means looking up online tutorials and digging into the documentation.
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© DevTeam.Space. Confidential and proprietaryQuestion 9: Tell me about a time you received feedback on a task
Requirement: Following instructions and receiving feedback
Answer: Look to see if the candidate can accept, understand and act on feedback.
Question 10: Describe how you would approach solving (some problem) on a high level?
Requirement: Thinking like a programmer
Answer: In this question, you should choose a problem that is directly related to the work the
candidate will actually be doing on your AngularJS project. You aren’t looking for a perfect answer
or even necessarily a correct answer. Instead, listen to how they approach solving a problem, their
ability to break a problem down into parts, and if they can anticipate problems.
AngularJS Advanced Interview Questions
In case you are looking for an expert, here are interview questions and answers for experienced
AngularJS developers to conduct a deeper technical interview.
An expert AngularJS developer has to know the AngularJS framework inside and out. But, you’re
looking for more than that. Ideal candidates will be able to design efficient applications, write clean
and robust code, work effectively with your team, and pass on their experience to junior developers.
Skill Requirements for Senior Angular JS Developers
● Expert AngularJS knowledge
● MVC Design Pattern
● Designing for specific requirements (e.g. security, scalability, optimization)
● Asynchronous programming
● Maintaining and upgrading applications
● Experience in frameworks/toolkits/libraries you use
● Efficient programming and clean code
● Debugging
● End-to-end and unit testing
● Leadership skills
● Clear communication skills
● Mentoring less experienced developers
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© DevTeam.Space. Confidential and proprietaryExample AngularJS Advanced Interview Questions and Answers
Note: Important keywords are underlined in the answers. Listen out for them!
Question 11: What are some advantages of using AngularJS framework?
Requirement: Expert AngularJS knowledge
Answer: Advantages of using the AngularJS framework include:
● Features like 2-way data binding mean less code than writing with just Javascript
● Code is easier to understand and less prone to errors
● It saves time for developers by doing a lot of the work for them like writing tedious DOM
manipulation tasks
● In many cases, it has faster performance than traditional web development techniques
● Can give web apps the feel of a desktop application
● It separates out the code of an application to make it easier for multiple developers to work
on an app and easier to test
● Big developer community
Question 12: What are some common ways of communicating between different modules of your
AngularJS app?
Requirement: Expert AngularJS knowledge
Answer: Events, services, assigning models on $rootScope, directly using $parent, $$childHead,
$$nextSibling or controllerAs when multiple controllers are being used.
Question 13: What are some disadvantages and limitations of using AngularJS framework?
Requirement: Expert AngularJS knowledge
Answer: Disadvantages of using the AngularJS framework include:
● Sometimes multiple ways to do the same thing, it isn’t clear which is the best
● Problems like too many watchers can severely slow down an application if you don’t know
what you’re doing
● You might need to create new implementations as your app grows. Angular implementations
don’t always scale well
● Not so mobile friendly
● Large and complex applications can get laggy
Question 14. What is the role of $routeProvider in AngularJS?
Requirement: Expert AngularJS knowledge, MVC Design Pattern
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© DevTeam.Space. Confidential and proprietaryAnswer: The $routeProvider is used to configure routes within an AngularJS application. In a Single
Page Application (SPA) you want to navigate to different pages without reloading the page. The
“ngRoute” routes your application to different pages configured with $routeProvider without
reloading the page.
Question 15. What is the main thing that you would need to change if you were to migrate from
AngularJS 1.4 to AngularJS 1.5?
Requirement: Expert AngularJS knowledge
Answer: You would need to update the app to the new AngularJS components by changing
.directive to .component.
Question 16: Give an example of a type of an application that could be built-in AngularJS, but
shouldn’t.
Requirement: Expert AngularJS knowledge
Answer: Here you’re probing for knowledge on the limitations of the AngularJS framework. Some
examples could be:
● Highly-secure applications – As AngularJS is a Javascript only framework highly secure
authentication is difficult
● Degradable applications – If a client doesn’t have Javascript running, the app won’t really
work at all
● Mobile first applications
● Games
Question 17: What are templates in AngularJS? Give a code example.
Requirement: Expert AngularJS knowledge, MVC Design Pattern
Answer: Templates are the HTML part of an AngularJS app. They are written in HTML but contain
AngularJS-specific elements and attributes. AngularJS combines the template with information from
the model and controller to render the dynamic view that a user sees in the browser. Basically, it
allows data to be injected into the HTML page.
● Directive – An attribute or element that augments an existing DOM element or represents a
reusable DOM component.
● Markup – The double curly brace notation {{ }} to bind expressions to elements is built-in
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© DevTeam.Space. Confidential and proprietaryAngularJS markup.
● Filter – Formats data for display.
● Form controls – Validates user input.
The following code snippet shows a template with directives and curly-brace expression bindings
from the AngularJS Developer Guide:
{{buttonText}}
Question 18: What is dependency injection and how does it work?
Requirement: Expert AngularJS knowledge
Answer: AngularJS was designed to highlight the power of dependency injection, a software design
pattern that places an emphasis on giving components their dependencies instead of hardcoding
them within the component. For example, if you had a controller that needed to access a list of
customers, you would store the actual list of customers in a service that can be injected into the
controller instead of hardcoding the list of customers into the code of the controller itself. In
AngularJS you can inject values, factories, services, providers, and constants.
Question 19: How do you share data between controllers in AngularJs?
Requirement: Expert AngularJS knowledge
Answer: We can share data by creating a service, Services are the easiest, fastest and cleanest way
to share data between controllers in AngularJs.
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© DevTeam.Space. Confidential and proprietaryThere are also other ways to share data between controllers, including:
● Using Events
● $parent, nextSibling, controllerAs
● Using the $rootScope
Question 20: What are promises in AngularJS? How do you use them in AngularJS? Give a quick
code example.
Requirement: Expert AngularJS knowledge, Asynchronous programming
Answer: Promises are a way of executing asynchronous functions using their return values when
they are finished processing. They are like a cleaner way of doing callbacks. $q is the built-in service
in AngularJS to use promises.
Here’s a basic example from the AngularJS docs:
function asyncGreet(name) {
// perform some asynchronous operation, resolve or reject the promise
when appropriate.
return $q(function(resolve, reject) {
setTimeout(function() {
if (okToGreet(name)) {
resolve('Hello, ' + name + '!');
} else {
reject('Greeting ' + name + ' is not allowed.');
}
}, 1000);
});
}
var promise = asyncGreet('Robin Hood');
promise.then(function(greeting) {
alert('Success: ' + greeting);
}, function(reason) {
alert('Failed: ' + reason);
});
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© DevTeam.Space. Confidential and proprietaryQuestion 21: Give a brief explanation of the AngularJS digest cycle?
Requirement: Expert AngularJS knowledge, Application optimization and performance
Answer: AngularJS has a feature called two-way data binding. If the user makes some change in an
application, such as clicking a button, this change is updated in the model (or $scope) part of the
application. The digest cycle is how this data binding is implemented in AngularJS. During a digest
cycle, AngularJS compares the old values with the new ones to check if anything has changed. This
is also called a dirty check. The $watch() and $digest() functions are used and the digest cycle is
triggered automatically.
Question 22: How can you decrease digest cycle time? What effect will this have on an
application?
Requirement: Expert AngularJS knowledge
Answer: Digest cycle time is largely determined by the number of watchers. To decrease digest
cycle time, try to reduce the number of watchers. It could also be the case that some watchers are
working too hard. Decreasing digest cycle time will make the app faster.
Question 23: What’s the difference between unit testing and end-to-end testing? What are some
testing tools you would use for an AngularJS application?
Requirement: End-to-end and unit testing
Answer: Unit testing is a technique to test that isolated segments of code are functioning properly.
End-to-end testing involves checking that entire sets of components to make sure they are working
together properly and that the application is working as you would expect.
End-to-end tests often simulate user interactions to test that an app is functioning as it should.
Jasmine, Karma and Protractor are all great testing tools.
Open-Ended Questions
Once you’ve established that your developer is an AngularJS expert you should continue the
interview asking some less technical questions, to spark a discussion. Tailor those questions to fit
your own job requirements and don’t be afraid to ask follow up questions!
Question 24: Describe a time you fixed a bug in a complex system. How did you approach the
problem? What debugging tools did you use? What did you learn from this experience?
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© DevTeam.Space. Confidential and proprietaryRequirement: Debugging, Breaking down a problem into parts
Debugging is one of the key skills for any software developer. However, the real skill is in breaking
the problem down in a practical way rather than finding small errors in code snippets. Debugging
often takes hours or even days, so you don’t have time in an interview setting. Asking these
questions will give you an idea of how your candidate approaches errors and bugs.
Answer: In the candidate’s response you should look out for things like:
● A measured, scientific approach
● Breaking down the problem into parts
● Finding out how to reproduce the error
● Expressing and then testing assumptions
● Looking at stack traces
● Getting someone else to help/take a look
● Searching the internet for others that have had the same problem
● Writing tests to check if the bug returns
● Checking the rest of the code for similar errors
● Turn problems into learning experiences
Question 25: What’s the most important thing to look for or check when reviewing another team
member’s code?
Requirement: Mentoring less experienced developers, Leadership skills
Answer: Here you’re checking for analysis skills, knowledge of mistakes that less experienced
developers make, keeping in mind the larger project and attention to detail.
Question 26: What tools & practices do you consider necessary for Continuous Integration and
Delivery of an AngularJS application?
Requirement: DevOps systems design, Maintaining and upgrading applications
Summary
Hiring the right people for your development team is critical to the success of your project.
Remember that you should not be aiming to hire the perfect AngularJS developer, but rather the
right person for the job at hand.
With the help of this information and sample interview questions on AngularJS, you can ensure that
the hiring process goes smoothly and successfully – allowing you to hire a great programming team
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© DevTeam.Space. Confidential and proprietaryto get your project completed on time and on budget.
Finally, you can simply print out this ready-to-use cheat sheet of questions and answers and bring it
with you to the interview. your candidates.
Happy Hiring!
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