Best AngularJS Interview Questions Answers for Selection

Best AngularJS Interview Questions Answers for Selection Best AngularJS Interview Questions Answers for Selection10 min read Read ­ing Time: 8 min ­utesBefore div ­ing into Angu ­lar ­JS inter ­view ques ­tions and answers we should have a lit ­tle knowl ­edge about what is Angu ­lar ­JS exact ­ly. While there are so many web appli ­ca ­tion frame ­works avail ­able in the mar ­ket, devel ­op ­ers still try to run after a frame ­work that is cheap, sus ­tain ­able and easy to code. Some of them are even open source such as Angu ­lar ­JS, Ruby on Rails, ASP.NET, Djan ­go, etc. But in this blog, we’ll con ­fine our ­selves to one major web appli ­ca ­tion frame ­work and that is Angu ­lar appli ­ca ­tion. These days pro ­gram ­mers are exten ­sive ­ly using Angu ­lar ­JS. There are a few fea ­tures that you should remem ­ber before sit ­ting in an inter ­view. The points list ­ed below will also help you in get ­ting the Angu ­lar ­JS inter ­view ques ­tions and answers right too. Impressive Features Of AngularJs Angu ­lar JS is a struc ­tured and more effi ­cient frame ­work that can cre ­ate Rich Inter ­net Appli ­ca ­tions (RIA). It pro ­vides the coder with an option to write the client-side appli ­ca ­tion using a JavaScrip ­t’s Mod ­el View Con ­troller struc ­ture. It is open-source hence is com ­plete ­ly free and used by count ­less thou ­sands of devel ­op ­ers around the world. Angu ­lar ­JS is licensed under the Apache license ver ­sion 2.0. These fea ­tures may seem to you like the ­o ­ry ques ­tions but the one thing the inter ­view ­er wants to make sure is to have a can ­di ­date whose base is strong. And when you know these ques ­tions you can eas ­i ­ly crack your Angu ­lar ­JS inter ­view and hence it increas ­es your chance of get ­ting select ­ed too. Advantage of AngularJS: More ­over, Angu ­lar ­JS has its advan ­tages such as: Angu ­lar ­JS can test the code using unit test ­ing. Angu ­lar ­JS is famous for its prop ­er ­ty of using reusable com ­po ­nents. Devel ­op ­ers can achieve more func ­tion ­al ­i ­ty using short ­codes with Angu ­lar ­Js. Angu ­lar ­JS sup ­ports the famous MVC (Mod ­el View Con ­troller) struc ­ture. The frame ­work uses two ways of data bind ­ing. Angu ­lar ­JS sup ­ports Client-Serv ­er com ­mu ­ni ­ca ­tion. It sup ­ports ani ­ma ­tion, mak ­ing it stand out from oth ­er web appli ­ca ­tion frame ­works. Know ­ing the pros and cons of a frame ­work you are work ­ing on, makes a good impres ­sion while you sit for the inter ­view. Some ­times an inter ­view ­er wants to check as to why a per ­son is work ­ing on this par ­tic ­u ­lar frame ­work when there are numer ­ous oth ­er frame ­works avail ­able in the mar ­ket. These Angu ­lar ­JS inter ­view ques ­tions and answers make sure that the next time you sit for an inter ­view, you remem ­ber all the details about the frame ­work. How ­ev ­er, you need to be well pre ­pared for an inter ­view that you face while search ­ing for a job. Read in detail on how to pre ­pare for an inter ­view here. Now with ­out wast ­ing any more time, let’s dive straight into Angu ­lar JS inter ­view ques ­tions and answers. Commonly Asked Questions AngularJS Interview Questions: 1. Explain “scope” in terms of AngularJS and why is it important? Answer: Scope acts as a bind ­ing force between the appli ­ca ­tion con ­troller and the view in Angu ­lar ­JS. It con ­tains the appli ­ca ­tion’s data and meth ­ods. Angu ­lar ­JS cre ­ates a dif ­fer ­ent scope hier ­ar ­chy for each con ­troller and hence data meth ­ods of one $scope are not avail ­able to anoth ­er con ­troller. 2. What is the meaning of services in AngularJS, explain in brief? Answer: To car ­ry out a spe ­cif ­ic task, ser ­vices are used. They are the sin ­gle ­ton objects. The ser ­vices can be called con ­trollers, direc ­tives, fil ­ters, etc. 3. Define Angular Expression in AngularJS? Answer: Expres ­sions are cod ­ed snip ­pets which are placed in bind ­ings for exam ­ple {{ expres ­sion }} There are a few dif ­fer ­ences that make it dif ­fer ­ent from the javascript expres ­sions and these are: Javascript expres ­sions are eval ­u ­at ­ed against the glob ­al win ­dow where ­as, in Angu ­lar, they are eval ­u ­at ­ed against a scope object. You can not use Loops, con ­di ­tion ­als or excep ­tions in an angu ­lar expres ­sion. 4. List all the directives used in the AngularJS application. Answer: It extends the HTML and acts as a mark ­er on a DOM that directs Angu ­lar ­JS to attach a spec ­i ­fied behav ­ior to the DOM ele ­ment. This is the ng-mod ­el. 5. Explain Angular. Answer: Angu ­lar plays a major role in the devel ­op ­ment of sin ­gle-page appli ­ca ­tions or SPA. It also pro ­vides the pro ­gram ­mer with a set of ready-to-use mod ­ules that makes it eas ­i ­er to devel ­op a sin ­gle page appli ­ca ­tion. Plus, it also has fea ­tures like built-in data stream ­ing, mod ­u ­lar CLI and types safe ­ty. With these fea ­tures, Angu ­lar can be con ­sid ­ered as a full-fledged web frame ­work. Tip: Though this whole blog is to make the begin ­ners pre ­pare for Angu ­lar ­JS inter ­view ques ­tions. Know ­ing the dif ­fer ­ence between Angu ­lar and Angu ­lar ­JS allows the inter ­view ­er to eval ­u ­ate the can ­di ­date per ­fect ­ly. So while prepar ­ing for the Angu ­lar ­JS inter ­view ques ­tions and answers, don’t for ­get to have a look at the dif ­fer ­ent ver ­sions of the frame ­work as well as the basic syn ­tax of the frame ­work. 6. Explain data binding in AngularJS? Answer: Data bind ­ing in Angu ­lar ­JS is the auto ­mat ­ed flow of data between the mod ­el and view in MVC struc ­ture. There are 2 ways in Angu ­lar ­JS for data bind ­ing and these are: Data min ­ing in clas ­si ­cal tem ­plate sys ­tems Data bind ­ing in angu ­lar tem ­plates 7. Explain the compilation steps in HTML? Answer: The HTML code is first parsed into Doc ­u ­ment Object Mod ­el i.e DOM through the stan ­dard brows ­er API. Then a com ­pi ­la ­tion of the doc ­u ­ment object mod ­el is per ­formed by call ­ing the $com ­plile() method. The scope is linked with the tem ­plate by call ­ing the link ­ing func ­tion that is returned from step 2. 8. What are a few disadvantages of the AngularJS framework? Answer: Angu ­lar ­JS is not a secure frame ­work. To avoid any glitch ­es serv ­er-side authen ­ti ­ca ­tion is nec ­es ­sary to keep an appli ­ca ­tion safe. It is not degrad ­able, that means if the user dis ­ables the javascript frame ­work, then a basic page will be vis ­i ­ble and noth ­ing else. 9. Discuss the key difference between backbone.js and AngularJS? Answers: To devel ­op an appli ­ca ­tion in HTML 5, Angu ­lar ­JS com ­bines var ­i ­ous func ­tion ­al ­i ­ties using libraries. Most of these libraries are third-par ­ty libraries. Where ­as Backbone.js does its job indi ­vid ­u ­al ­ly with ­out tak ­ing any help from oth ­er third-par ­ty libraries. 10. Define templates in AngularJS? Answers: Tem ­plates are a more fur ­nished view that has infor ­ma ­tion from both the con ­troller and the mod ­el. They can be com ­pressed in a sin ­gle file, for exam ­ple, front.html or “par ­tials” can be used in mul ­ti ­ple views for exe ­cut ­ing the same. 11. Explain anMVC structure? MVC struc ­ture or in oth ­er words Mod ­el View Con ­troller is a soft ­ware design pat ­tern. Many frame ­works fol ­low it to have a smooth tran ­si ­tion of data while devel ­op ­ing any web appli ­ca ­tion. It has main ­ly 3 parts such as: Mod ­el: It is respon ­si ­ble for main ­tain ­ing data and is it the low ­est lev ­el of the pat ­tern View: It helps in dis ­play ­ing a por ­tion or com ­plete data to the user Con ­troller: It con ­trols the inter ­ac ­tion between the Mod ­el and the View. 12. How to use a factory method in the AngularJS framework? Answer: To use a fac ­to ­ry method, we first have to define a fac ­to ­ry and after ­ward assign a method to it. var mainApp = angular.module(“mainApp”, []); mainApp.factory(‘MathService’, func ­tion() { var fac ­to ­ry = {}; factory.multiply = function(a, b) { return a * b } return fac ­to ­ry; }); 13. Explain what are “functions” in javascript and also how will you declare them in the code? Answer: Tip: (Func ­tions are a very impor ­tant part of the javascript and most of the inter ­view ­ers want to know whether the can ­di ­date knows about “func ­tions” in javascript. So it is impor ­tant to know about func ­tions when ­ev ­er you sit to pre ­pare for Angu ­lar ­JS inter ­view ques ­tions. In javascript, func ­tions are the fun ­da ­men ­tal build ­ing blocks. It is a pro ­ce ­dure and is defined as a set of state ­ments that are used to per ­form a task or eval ­u ­ate a val ­ue. For using a func ­tion in javascript, it must be defined some ­where in the scope in angu ­lar ­js from which you wish to call it. Defin ­ing a func ­tion in javascript : It con ­sists of a “func ­tion” key ­word which is fol ­lowed by the name of the func ­tion, list of para ­me ­ters passed to the func ­tions and the state ­ments in javascript that define the func ­tion. These should be specif ­i ­cal ­ly enclosed in curly brack ­ets {..}. For exam ­ple, the below code defines a func ­tion named “addi ­tion”: func ­tion addition(number) { return number+number; } 14. What do you mean by “objects” in javascript ? Answer: Javascript is an object-based lan ­guage, so every ­thing is an object in the lan ­guage. It is more tem ­plate-based in com ­par ­i ­son to being class-based. In javascript, we can direct ­ly cre ­ate an object here with ­out cre ­at ­ing a class first. There are 3 dif ­fer ­ent ways in which we can cre ­ate an object: It can be using object lit ­er ­al ­By cre ­at ­ing an instance of Object direct ­ly ­We can use an object con ­struc ­tor too Here, we will dis ­cuss the syn ­tax one by one so that you have a fair idea about the same By Object Lit ­er ­al Syn ­tax: object={property1:value1,property2:value2.….propertyN:valueN} 2. Cre ­at ­ing an instance of Object direct ­ly Syn ­tax: varobjectname=new Object(); 3.By using an object con ­struc ­tor Here first, you need to cre ­ate a func ­tion with argu ­ments. This argu ­ment val ­ue is assigned in the cur ­rent object by using “this” key ­word. In this, “this” key ­word refers to the cur ­rent object. For exam ­ple : script func ­tion stud(id,name,rollno){ this.id=id; this.name=name; this.rollno=rollno; } s=new stud(110,“Vinay Kha ­tri”, 23451 ); document.write(s.id+” “+s.name+” “+.roll ­no); /script Out ­put of the above code: (110,Vinay Kha ­tri, 23451) 15. What are HTML Elements? Answer: An HTML ele ­ment gen ­er ­al ­ly con ­tains a start tag and an end tag and con ­tent is in between the tags: tagnameContent/tagname Few Exam ­ples Of HTML tags are : P: This tag is use ­ful in enclos ­ing a paragraph.H: Head ­ing of dif ­fer ­ent sizes can be writ ­ten in this.br: This is a break tag. Void Ele ­ments In HTML, some tags such as br don’t require an enclos ­ing tag. 16. What are the basic differences between link and compile? Answer: The basic require ­ment of link func ­tion is to reg ­is ­ter the DOM Lis ­ten ­ers and also cite the DOM manip ­u ­la ­tion. The com ­pile func ­tion on the oth ­er hand is basi ­cal ­ly used for col ­lect ­ing the direc ­tives and as well as tem ­plat ­ing DOM Manip ­u ­la ­tion. 17. What is a single page application? How can it be implemented along with Angular? Answer: Sin ­gle Page appli ­ca ­tions are those web apps which dynam ­i ­cal ­ly update the HTML page as and when the users inter ­act with the app. In SPA, the only change that hap ­pens is that the parts of the page may get refreshed. The page on the oth ­er hand is nev ­er reloaded. With this func ­tion ­al ­i ­ty, how ­ev ­er, the trips to the serv ­er are reduced. 18. What are the various types of filters in AngularJS? Answer: Num ­ber for ­mats a num ­ber into a string. Low ­er ­casefor ­mats a string into a low ­er case. Upper ­casefor ­mats a string into a upper case. Cur ­ren ­cyfor ­mats the num ­ber into a cur ­ren ­cy for ­mat. Fil ­terhelps select a sub ­set of items from with ­in an array. Datefor ­mats the date to a spe ­cif ­ic for ­mat as required. JSONfor ­mats the object into a Json string. Lim ­it reduces the array or string to a spe ­cif ­ic num ­ber of char ­ac ­ters or ele ­ments. 19. What are the differences between Directives and Services? Answer: This is one of the most asked Angu ­lar ­JS Inter ­view Ques ­tions and answers. One of the ways to com ­mu ­ni ­cate with con ­trollers is Ser ­vices. It is also pos ­si ­ble to inject one ser ­vice into anoth ­er. There are oth ­er func ­tions like log ­ging and authen ­ti ­ca ­tion which can also be done through Ser ­vices. Direc ­tives on the oth ­er hand are used for wrap ­ping things like jquery plu ­g ­ins or cre ­at ­ing wid ­gets. 20. Explain what is Singleton Pattern and how do you use it? Answer: In order to have only one object, the sin ­gle ­ton pat ­tern allows the lim ­i ­ta ­tion of a class’ instan ­ti ­a ­tion. The Sin ­gle ­ton pat ­tern can be enabled through the use of depen ­den ­cy injec ­tion and ser ­vices. These were the few impor ­tant Angu ­lar ­JS inter ­view ques ­tions and answers. Itcan be referred by begin ­ners as well as experts too who are think ­ing to brush up their knowl ­edge. Demand In The Market As a result of the demand in the mar ­ket, every com ­pa ­ny needs devel ­op ­ers who have inside knowl ­edge about the frame ­work. There ­fore to work on the frame ­work, it is impor ­tant to know what kind of ques ­tions you can expect when you sit for the inter ­view. This set ofAngu ­lar ­JS inter ­view ques ­tions and answers can help you build your base as well as pre ­pare you for your dream job too. Conclusion To sum up, Angu ­lar ­JS is one of the fastest-grow ­ing frame ­works and now has a large com ­mu ­ni ­ty work ­ing online too on var ­i ­ous plat ­forms. Sev ­er ­al devel ­op ­ers are exten ­sive ­ly using this frame ­work in their projects. This frame ­work is no doubt becom ­ing every devel ­op ­er’s favorite because itallows you to embed ani ­ma ­tion and many oth ­er cool fea ­tures too. angularjs interview questionsangularjs interview questions and answers