Top Javascript Interview Questions & Answers

Javascript defer vs async

Javascript defer vs async is a common question in Javascript interviews. Modern web applications deal with a lot of scripts. So, it is very important for a Javascript developer to know how to optimally load scripts on a webpage.

Functions

When to define methods on Prototype in Javascript?

Function constructors are the most popular way to create objects in Javascript. Classes can also used, however, classes are nothing but just a syntactic sugar on top of function constructors. Creating Objects Using a Function ConstructorHere's how we create objects in Javascript using a

Javascript Quiz

Test Your Javascript Skills - Object Iteration Order

An Object is a heavily used data structure in Javascript. Objects are used to store properties that are basically key value pairs. An important operation on the Object data structure is iteration - Going over the object properties one by one and possibly performing some operation on those.

Functions

Implement a .bind() polyfill

Writing your own .bind() implementation is a common question asked in Javascript interviews at companies like Microsoft, Walmart, Flipkart to name a few. Lets see how to tackle such problems in this post.

Javascript Quiz

Javascript Quiz - Binding Context

Identify a problem with the Javascript code below. Can you fix it?const city = { name: 'London', getCity: function() { return this.name; } }; const printCityName = getter => console.log(`The city name

Preparation Tips

Ultimate Javascript Interview Preparation Checklist

Never miss out on an important Javascript topic for your next interview. Here's a list of favorites.

Performance

Append a List of DOM Nodes

There are a number of uses cases where we need to create DOM nodes and append them to a list of nodes. Think about WhatApp Web, scroll up, older messages

Arrays

Implement Array Reduce

Assuming Javascript does not have an array reduce method, how would you implement one? Or in other words, implement a polyfill for array reduce in Javascript.

Preparation Tips

Javascript Interview Questions You'll Never be Asked

It's hard to find great interview resources for Javascript online. Many of us are dependent on our jobs to learn stuff. That however, does not work in the crazy world of Javascript.

Closures

Currying in Javascript - Top Interview Questions [Solved]

Currying is a powerful pattern in the Javascript language. Many libraries make use of this pattern. It is primarily based on the concept of closures. If you understand scopes and

Closures

Closure Inside Loops - JS Interview Question

Favourite of interviewers! A huge probability that you could be asked a question on closure inside loops in your Javascript interview. And let me tell you, your interviewer would definitely be impressed if you are able to answer it.