26/4/2021 md2pdf - Markdown to PDF
Hello World! Today I prepared a huge list of Javascript Interview Questions from this awesome repo,
their really cool and have lots of this kind of resources.
⚡ Giveaway ⚡
We are giving away any course you need on Udemy. Any price any course. Steps to enter the
giveaway
--> React to this post
--> Subscribe to our Newsletter <-- Very important
--> Extra: Join us at Discord to participate in our next events
Extra --> For beginners:
What is JS (Javascript)
JavaScript is a scripting or programming language that allows you to implement complex
features on web pages — every time a web page does more than just sit there and display static
information for you to look at — displaying timely content updates, interactive maps, animated
2D/3D graphics, scrolling video jukeboxes, etc. — you can bet that JavaScript is probably
involved. It is the third layer of the layer cake of standard web technologies. MDN
https://md2pdf.netlify.app 1/176
,26/4/2021 md2pdf - Markdown to PDF
What it used for?
To put things simply, JavaScript is an object orient programming language designed to make
web development easier and more attractive. In most cases, JavaScript is used to create
responsive, interactive elements for web pages, enhancing the user experience. Things like
menus, animations, video players, interactive maps, and even simple in-browser games can be
created quickly and easily with JavaScript. JavaScript is one of the most popular programming
languages in the world. BitDegree - What Is JavaScript Used For And Why You Should Learn It
Hello World In Javascript:
alert("Hello World") — Output data in an alert box in the browser window
confirm("Hello World") — Opens up a yes/no dialog and returns true/false depending on user cli
console.log("Hello World") — Writes information to the browser console, good for debugging pur
document.write("Hello World") — Write directly to the HTML document
prompt("Remember the like!") — Creates a dialogue for user input
Resources to learn it:
Mozilla’s JavaScript Guide JavaScript track on Codecademy: Interactive tutorials for beginners.
JavaScript for Cats by Max Ogden Eloquent JavaScript by Marijn Haverbeke Wikibooks’ JavaScript
book JavaScript Lectures by Douglas Crockford You Don't Know JS - Possibly the best book written on
modern JavaScript, completely readable online for free, or can be bought to support the author.
braziljs/js-the-right-way - An easy-to-read, quick reference for JS best practices, accepted coding
standards, and links around the Web. JSbooks - Directory of free JavaScript ebooks. Superhero.js - A
collection of resources about creating, testing and maintaining a large JavaScript code base. SJSJ -
Simplified JavaScript Jargon is a community-driven attempt at explaining the loads of buzzwords
making the current JavaScript ecosystem in a few simple words. How to Write an Open Source
JavaScript Library - A comprehensive guide through a set of steps to publish a JavaScript open source
library. JavaScript Tutorials - Learn Javascript online from a diverse range of user ranked online
tutorials. Functional-Light JavaScript - Pragmatic, balanced FP in JavaScript. Clean Code JavaScript -
Clean Code concepts adapted for JavaScript. List at GitHub - Awesome Javascript - By Alexandru
Gherasim
At Reddit - What 10 Things Should a Serious Javascript Developer Know Right
Now?
Scope. If you don't understand this intimately then you aren't that serious about this language.
This is the number one point intentionally and I cannot stress it enough.
Architecture. You don't have to be a master software architect, but if you cannot perform some
basic planning and put pieces together without massive layers of tooling you are an imposter.
https://md2pdf.netlify.app 2/176
,26/4/2021 md2pdf - Markdown to PDF
Expecting frameworks and other tools to simply do it for you isn't very impressive.
DOM. It is very common to see developers hiding from the DOM by layers of abstractions and
other stupid crap. querySelectors are great, but are also 2800x slower than the standard DOM
methods. That isn't trivial. These methods are super simple, so there is no valid excuse for
developers fumbling over this or hiding in fear. http://prettydiff.com/guide/unrelated_dom.xhtml
Node.js If you are a serious developer should have a pretty solid grasp of how to walk the file
system. You should understand how to conveniently read files as text or less conveniently read
files as bit for bit binary buffers.
Timing and asynchronous operations. Events, timers, network requests are all asynchronous and
separate from each other and exist both in Node and in the browser. You have to be able to
understand how to work with callbacks or promises.
Accessibility. The interactions imposed by JavaScript can present accessibility barriers. A serious
JavaScript developer is already familiar with WCAG 2.0 and knows how to work within its
recommendations or when to push back on violating business requirements.
Security. You need to have at least a basic understanding of security violations, security controls,
and privacy. You don't need to be a CISSP, but you need to be able to supply recommendations
and avoid obvious failures. If you cannot get this right in the most basic sense you aren't a
serious developer.
Data structures. You need to understand how to organize data in a way that allows the fastest
possible execution without compromising maintenance. This is something that is learned
through academic study and repeated experience writing applications.
Presentation and semantics. You really need to have a basic understanding how to properly
organize the content your users will consume and how to present in a consumable way
efficiently. This is something almost completely learned from experience only. You might think
CSS and HTML are simple skills that can be picked up when needed, but you would be absolutely
wrong.
Knowing when to avoid the bullshit. Many developers lack the years of experience to be
confident in their performance.... so some of these developers will try to fake it. Don't be an
imposter, because everybody will see straight through it. Hoping mountains of abstractions,
tooling, frameworks, compilers, and other bullshit will save you just bogs down your application
and screws over your teammates. If you aren't confident then be honest about that and seek
mentorship or get involved with open source software outside of work.
https://md2pdf.netlify.app 3/176
,26/4/2021 md2pdf - Markdown to PDF
Source
Table of Contents:
No. Questions
1 What are the possible ways to create objects in JavaScript
2 What is prototype chain
3 What is the difference between Call, Apply and Bind
4 What is JSON and its common operations
5 What is the purpose of the array slice method
6 What is the purpose of the array splice method
7 What is the difference between slice and splice
8 How do you compare Object and Map
9 What is the difference between == and === operators
10 What are lambda or arrow functions
11 What is a first class function
12 What is a first order function
13 What is a higher order function
14 What is a unary function
https://md2pdf.netlify.app 4/176
, 26/4/2021 md2pdf - Markdown to PDF
No. Questions
15 What is the currying function
16 What is a pure function
17 What is the purpose of the let keyword
18 What is the difference between let and var
19 What is the reason to choose the name let as a keyword
20 How do you redeclare variables in switch block without an error
21 What is the Temporal Dead Zone
22 What is IIFE(Immediately Invoked Function Expression)
23 What is the benefit of using modules
24 What is memoization
25 What is Hoisting
26 What are classes in ES6
27 What are closures
28 What are modules
29 Why do you need modules
30 What is scope in javascript
31 What is a service worker
32 How do you manipulate DOM using a service worker
33 How do you reuse information across service worker restarts
34 What is IndexedDB
35 What is web storage
36 What is a post message
37 What is a cookie
38 Why do you need a Cookie
39 What are the options in a cookie
40 How do you delete a cookie
41 What are the differences between cookie, local storage and session storage
https://md2pdf.netlify.app 5/176
Hello World! Today I prepared a huge list of Javascript Interview Questions from this awesome repo,
their really cool and have lots of this kind of resources.
⚡ Giveaway ⚡
We are giving away any course you need on Udemy. Any price any course. Steps to enter the
giveaway
--> React to this post
--> Subscribe to our Newsletter <-- Very important
--> Extra: Join us at Discord to participate in our next events
Extra --> For beginners:
What is JS (Javascript)
JavaScript is a scripting or programming language that allows you to implement complex
features on web pages — every time a web page does more than just sit there and display static
information for you to look at — displaying timely content updates, interactive maps, animated
2D/3D graphics, scrolling video jukeboxes, etc. — you can bet that JavaScript is probably
involved. It is the third layer of the layer cake of standard web technologies. MDN
https://md2pdf.netlify.app 1/176
,26/4/2021 md2pdf - Markdown to PDF
What it used for?
To put things simply, JavaScript is an object orient programming language designed to make
web development easier and more attractive. In most cases, JavaScript is used to create
responsive, interactive elements for web pages, enhancing the user experience. Things like
menus, animations, video players, interactive maps, and even simple in-browser games can be
created quickly and easily with JavaScript. JavaScript is one of the most popular programming
languages in the world. BitDegree - What Is JavaScript Used For And Why You Should Learn It
Hello World In Javascript:
alert("Hello World") — Output data in an alert box in the browser window
confirm("Hello World") — Opens up a yes/no dialog and returns true/false depending on user cli
console.log("Hello World") — Writes information to the browser console, good for debugging pur
document.write("Hello World") — Write directly to the HTML document
prompt("Remember the like!") — Creates a dialogue for user input
Resources to learn it:
Mozilla’s JavaScript Guide JavaScript track on Codecademy: Interactive tutorials for beginners.
JavaScript for Cats by Max Ogden Eloquent JavaScript by Marijn Haverbeke Wikibooks’ JavaScript
book JavaScript Lectures by Douglas Crockford You Don't Know JS - Possibly the best book written on
modern JavaScript, completely readable online for free, or can be bought to support the author.
braziljs/js-the-right-way - An easy-to-read, quick reference for JS best practices, accepted coding
standards, and links around the Web. JSbooks - Directory of free JavaScript ebooks. Superhero.js - A
collection of resources about creating, testing and maintaining a large JavaScript code base. SJSJ -
Simplified JavaScript Jargon is a community-driven attempt at explaining the loads of buzzwords
making the current JavaScript ecosystem in a few simple words. How to Write an Open Source
JavaScript Library - A comprehensive guide through a set of steps to publish a JavaScript open source
library. JavaScript Tutorials - Learn Javascript online from a diverse range of user ranked online
tutorials. Functional-Light JavaScript - Pragmatic, balanced FP in JavaScript. Clean Code JavaScript -
Clean Code concepts adapted for JavaScript. List at GitHub - Awesome Javascript - By Alexandru
Gherasim
At Reddit - What 10 Things Should a Serious Javascript Developer Know Right
Now?
Scope. If you don't understand this intimately then you aren't that serious about this language.
This is the number one point intentionally and I cannot stress it enough.
Architecture. You don't have to be a master software architect, but if you cannot perform some
basic planning and put pieces together without massive layers of tooling you are an imposter.
https://md2pdf.netlify.app 2/176
,26/4/2021 md2pdf - Markdown to PDF
Expecting frameworks and other tools to simply do it for you isn't very impressive.
DOM. It is very common to see developers hiding from the DOM by layers of abstractions and
other stupid crap. querySelectors are great, but are also 2800x slower than the standard DOM
methods. That isn't trivial. These methods are super simple, so there is no valid excuse for
developers fumbling over this or hiding in fear. http://prettydiff.com/guide/unrelated_dom.xhtml
Node.js If you are a serious developer should have a pretty solid grasp of how to walk the file
system. You should understand how to conveniently read files as text or less conveniently read
files as bit for bit binary buffers.
Timing and asynchronous operations. Events, timers, network requests are all asynchronous and
separate from each other and exist both in Node and in the browser. You have to be able to
understand how to work with callbacks or promises.
Accessibility. The interactions imposed by JavaScript can present accessibility barriers. A serious
JavaScript developer is already familiar with WCAG 2.0 and knows how to work within its
recommendations or when to push back on violating business requirements.
Security. You need to have at least a basic understanding of security violations, security controls,
and privacy. You don't need to be a CISSP, but you need to be able to supply recommendations
and avoid obvious failures. If you cannot get this right in the most basic sense you aren't a
serious developer.
Data structures. You need to understand how to organize data in a way that allows the fastest
possible execution without compromising maintenance. This is something that is learned
through academic study and repeated experience writing applications.
Presentation and semantics. You really need to have a basic understanding how to properly
organize the content your users will consume and how to present in a consumable way
efficiently. This is something almost completely learned from experience only. You might think
CSS and HTML are simple skills that can be picked up when needed, but you would be absolutely
wrong.
Knowing when to avoid the bullshit. Many developers lack the years of experience to be
confident in their performance.... so some of these developers will try to fake it. Don't be an
imposter, because everybody will see straight through it. Hoping mountains of abstractions,
tooling, frameworks, compilers, and other bullshit will save you just bogs down your application
and screws over your teammates. If you aren't confident then be honest about that and seek
mentorship or get involved with open source software outside of work.
https://md2pdf.netlify.app 3/176
,26/4/2021 md2pdf - Markdown to PDF
Source
Table of Contents:
No. Questions
1 What are the possible ways to create objects in JavaScript
2 What is prototype chain
3 What is the difference between Call, Apply and Bind
4 What is JSON and its common operations
5 What is the purpose of the array slice method
6 What is the purpose of the array splice method
7 What is the difference between slice and splice
8 How do you compare Object and Map
9 What is the difference between == and === operators
10 What are lambda or arrow functions
11 What is a first class function
12 What is a first order function
13 What is a higher order function
14 What is a unary function
https://md2pdf.netlify.app 4/176
, 26/4/2021 md2pdf - Markdown to PDF
No. Questions
15 What is the currying function
16 What is a pure function
17 What is the purpose of the let keyword
18 What is the difference between let and var
19 What is the reason to choose the name let as a keyword
20 How do you redeclare variables in switch block without an error
21 What is the Temporal Dead Zone
22 What is IIFE(Immediately Invoked Function Expression)
23 What is the benefit of using modules
24 What is memoization
25 What is Hoisting
26 What are classes in ES6
27 What are closures
28 What are modules
29 Why do you need modules
30 What is scope in javascript
31 What is a service worker
32 How do you manipulate DOM using a service worker
33 How do you reuse information across service worker restarts
34 What is IndexedDB
35 What is web storage
36 What is a post message
37 What is a cookie
38 Why do you need a Cookie
39 What are the options in a cookie
40 How do you delete a cookie
41 What are the differences between cookie, local storage and session storage
https://md2pdf.netlify.app 5/176
