1.What are the primitive and non-primitive data types, What is the difference between undefined and null.
2.Arrays - push,pop,shift,unshift,splice,
delete,remove. The difference between delete and remove with array.
3.Function,Default return value of JS function, Closure, Scope, Nested function - scope, Lexical Scope.
4.What is self invoking anonymous function? IIFE
5.What is anonymous function?
6.Why do we need IIFE? [To avoid global declarations/leakages]
7.What is event bubbling?
8.Explain the phases of event handler in JS? or How the events are handled in JS?
9.What is an object literal?
10.Do we have classes in JS? Till ECMA5, there is no keyword called class to create classes, but you can use constructor
function to implement classes in JS.
11.Explain "this" keyword.
12.By default "this" keyword refers to which object? - Window
13.What is strict mode?
14.Explain the term DOM?
15.How will make an AJAX call from JS?
16.Explain what is AJAX? Which object do you use to implement AJAX in JS?
17.Explain the use addEventListener method. What is the significance of true or false value as third argument?
18.What is the purpose of "arguments" object in a function?
19.Why do we use call or apply method to call the function?
20.Difference between object created using object literal and using constructor.
21.Explain prototype property of function.
22.try..catch ..finally - throw - error handling.
23.Java script design patterns //https://addyosmani.com/resources/essentialjsdesignpatterns/book/#designpatternsjavascript
24.What is a namespace? How will you create a namespace in
javascript
?
25.How will you create a module in
javascript
?
26.What are Promises? [Async call] Promise - resolve state. Various states of promise.
27.Explain the difference between JSON and JSONP. - cross domain-
28.What is the cross domain reference issue? CORS Enabled WEB API.
29.What are recursive functions?
30.What are call-back functions? - calling a function as a parameter of other function.
31.How will you implement inheritance in
Javascript
? var child = Object.create(parent); Though there are many way
to implement inheritance.
32.Explain the term hoisting.
33.Pub/Sub
34.Getter/Setter
35.Debounce/Throttle //https://sking7.github.io/articles/1248932487.html
we use the debounce inside our analytics for debounce the 'scroll' event, because we are relaying on the
'scroll' event to check if the experiment is in the viewPort, and we do not want to get every 'scroll' event
because that will be so lagg,
36.Function Currying
37.Function Generators