JavaScript Interview Questions
Preparing for a job interview requires studying to refresh your knowledge and skills. This collection of JavaScript interview questions is designed to cover some commonly-asked interview questions, using concise answers and simple examples.
What is the difference between JavaScript's equality operators?
Learn all you need to know about the differences between JavaScript's double equals and triple equals operators.
JavaScript, Type · Jun 12, 2021
What are truthy and falsy values in JavaScript?
JavaScript uses type coercion in Boolean contexts, resulting in truthy or falsy values. Get a hang of how it all works in this quick guide.
JavaScript, Type · Sep 12, 2021
What is the difference between an expression and a statement in JavaScript?
JavaScript distinguishes expressions and statements. Learn their differences in this short article.
JavaScript, Type · Nov 7, 2021
What's the difference between undeclared, undefined and null in JavaScript?
JavaScript has three different empty states for variables. Learn their differences and how you can check for each one.
JavaScript, Type · Jun 12, 2021
What is hoisting in JavaScript?
Hoisting comes up a lot during JavaScript interviews. It's a concept that may require some getting used to, so read our guide to learn more.
JavaScript, Type · Jun 12, 2021
Understanding JavaScript variables and scopes
JavaScript developers often get confused by JavaScript's variables and scope. Here's a quick guide to understanding these concepts.
JavaScript, Type · Jun 12, 2021
What is a callback function?
JavaScript uses callback functions quite a lot. From event listeners to asynchronous code, they're an invaluable tool you need to master.
JavaScript, Function · Oct 3, 2021
Is JavaScript pass-by-value or pass-by-reference?
How JavaScript handles passing data is a source of confusion and bugs for many developers, especially when it comes to object types.
JavaScript, Function · Dec 5, 2021
What are promises in JavaScript? In which states can a promise be?
JavaScript's promises represent the eventual completion (or failure) of asynchronous operations and their resulting value.
JavaScript, Function · Oct 24, 2021
What is the difference between synchronous and asynchronous code in JavaScript?
Understanding the differences between synchronous and asynchronous code is a crucial piece of knowledge for every web developer.
JavaScript, Function · Nov 14, 2021
How does JavaScript's prototypal inheritance differ from classical inheritance?
Understanding the difference between these two object-oriented programming paradigms is key to taking your skills to the next level.
JavaScript, Object · Nov 21, 2021
Understanding the "this" keyword in JavaScript
JavaScript's
thiskeyword can confuse beginners and veterans alike. Learn how it works in different scenarios and start using it correctly.JavaScript, Function · Jun 12, 2021
How do I clone an object in JavaScript?
Learn how JavaScript handles mutable data, such as objects and arrays, and understand how shallow cloning and deep cloning work.
JavaScript, Object · Jun 12, 2021
How can I clone an array in JavaScript?
Pick up a few new tricks which you can use to clone arrays in JavaScript.
JavaScript, Array · Jun 12, 2021
How do I compare two objects in JavaScript?
Learn how you can compare two objects in JavaScript using various different techniques.
JavaScript, Object · Sep 26, 2021
