JavaScript Interview Questions and Answers

JavaScript Interview Questions and Answers aim to enhance comprehension of fundamental concepts, programming functionality, JavaScript data structures, and advanced JavaScript concepts. They serve as a valuable resource for both beginners and experienced individuals seeking to expand their knowledge.

These questions often include references to more extensive information sources. Presented below are a few examples of Advanced JavaScript Interview Questions and Answers suitable for individuals at various stages of their career.

What is memoization?

Memoization is a technique in programming where the results of expensive function calls are cached so that if the same inputs occur again, the cached result is returned instead of re-computing the result, which can improve performance.

What is Currying in javascript?

Currying is a functional programming concept in JavaScript where a function that takes multiple arguments is transformed into a series of functions that take one argument each. It allows you to create more specialized functions by partially applying arguments.

What is Object Destructuring?

Object destructuring is a feature in JavaScript that allows you to extract properties from objects and bind them to variables. It provides a concise way to unpack values from objects, making code cleaner and more readable.

Does JavaScript support automatic type conversion?

Yes, JavaScript supports automatic type conversion, also known as type coercion. This means that JavaScript will attempt to convert values from one data type to another in certain situations, such as when performing operations between different data types.

What is Same Origin Policy?

The Same Origin Policy is a security measure in web browsers that restricts web pages from making requests to a different domain than the one that served the web page. This policy helps prevent unauthorized data access and enhances security on the web.

How are JavaScript and ECMA Script related?

ECMAScript (often abbreviated as ES) is the standardized scripting language specification that JavaScript is based on. JavaScript is the most popular implementation of the ECMAScript specification, but there are other implementations as well.

What is prototypal Inheritance?

Prototypal inheritance is a mechanism in JavaScript where objects can inherit properties and methods from other objects, called prototypes. Each object has an internal link to its prototype, and if a property or method is not found on the object itself, JavaScript looks for it in the prototype chain.

What is negative infinity in JavaScript?

Negative infinity is a special value in JavaScript that represents the lowest possible numerical value. It's used to represent extremely small or unreachable values in mathematical calculations.

Explain WeakSet in JavaScript

WeakSet is a built-in object in JavaScript that allows you to store a collection of weakly held object references. Unlike regular sets, WeakSets do not prevent their referenced objects from being garbage collected if there are no other strong references to those objects, making them useful for managing memory in specific cases.

What are arrow functions?

Arrow functions are a concise syntax introduced in ES6 for creating functions in JavaScript. They have a shorter syntax compared to traditional function expressions and automatically capture the surrounding context's this value, making it particularly useful for certain use cases.

What is the use of the "debugger" keyword?

The "debugger" keyword is used in JavaScript to create a breakpoint in your code. When a debugger is present, execution will pause at the "debugger" statement, allowing developers to inspect variables, step through code, and troubleshoot issues more effectively using browser developer tools or debugging environments.

Last Updated : 24 Aug 2023



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