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100+ JavaScript Coding Practice Test Questions Answers 2026
Role Play
Rating: 4.1 out of 5(62 ratings)
19,164 students

100+ JavaScript Coding Practice Test Questions Answers 2026

100+ JavaScript Interview Coding Questions and Answers (Solution Code with Detailed Explanations)
Role Play
Created byJitendra Suryavanshi
Last updated 1/2026
English

What you'll learn

  • Confidence Boost for Complex Scenarios
  • Think Like an Expert Developer
  • Hands-On, Realistic Practice
  • Effective Coding Patterns and Best Practices
  • Application to Real-World Scenarios

Coding Exercises

This course includes our updated coding exercises so you can practice your skills as you learn.

See a demo
Image of coding exercise example

Course content

3 sections • 5 lectures • 46m total length

  • Challenge Overview3:36
  • Introducing JavaScript Challenges6:44
  • Challenges Lists30:30
  • How to Debug Effectively in JavaScript: A Step-by-Step Guide2:35
  • Think Before You Code: A Structured Approach to Problem Solving2:57
  • Print "Hello, World!" Using JavaScript
  • JavaScript Program to Add Two Numbers
  • JavaScript Program to Calculate the Square Root of a Number
  • Calculate the Area of a Triangle in JavaScript
  • Solve a Quadratic Equation in JavaScript
  • Swap Two Variables in JavaScript
  • Convert Kilometers to Miles in JavaScript
  • JavaScript Program to Generate a Random Number within a Range
  • Determine if a Number is Positive, Negative, or Zero
  • Determine If a Number is Odd or Even
  • Find the Largest of Three Numbers
  • Check If a Number is Prime in JavaScript
  • Print Prime Numbers in a Given Range Using JavaScript
  • Find the Factorial of a Number in JavaScript
  • Generate Multiplication Table for a Given Number
  • Print Fibonacci Sequence in JavaScript
  • Check if a Number is an Armstrong Number
  • JavaScript Program to Find Armstrong Numbers Within a Given Range
  • Build a Simple Calculator Using JavaScript Functions
  • Find the Sum of the First N Natural Numbers
  • Check If Two Numbers Share the Same Last Digit
  • Find the Highest Common Factor (HCF) or Greatest Common Divisor (GCD) of Two Numbers
  • Find the Least Common Multiple (LCM) of Two Numbers
  • Find All Factors of a Number in JavaScript
  • Guess a Random Number in JavaScript
  • Recursive Fibonacci Sequence Display in JavaScript
  • Recursive Factorial Function in JavaScript
  • Convert Decimal to Binary in JavaScript
  • JavaScript Program to Get ASCII Value of a Character
  • Check if a String is a Palindrome
  • Sort Words Alphabetically
  • JavaScript Function to Substitute String Characters
  • Reverse a String in JavaScript
  • Count Character Occurrences in a String
  • Convert the First Letter of Each Word to Uppercase in a String
  • JavaScript Program to Delete an Object Property
  • Check for Key Presence in JavaScript Object
  • Clone a JavaScript Object
  • Iterate Through Object Properties in JavaScript
  • Merge Properties of Two Objects in JavaScript
  • Count the Number of Properties in an Object
  • Add a Key/Value Pair to a JavaScript Object
  • Replace All Occurrences of a Substring in a String
  • Create Multiline Strings in JavaScript
  • Convert Numbers to Currency Format in JavaScript
  • Random String Generator
  • Check if a String Starts with a Substring
  • Trim a String in JavaScript
  • Convert JavaScript Object to String
  • Check if a String Contains a Substring in JavaScript
  • String Comparison in JavaScript
  • Convert String to Base64 in JavaScript
  • Replace All Instances of a Character in a String
  • Replace Line Breaks with Spaces in a String
  • Display Current Date and Time Using JavaScript
  • JavaScript Program to Format a Date
  • Display the Current Date using JavaScript Functions
  • Create a Countdown Timer in JavaScript
  • Remove a Specific Item from an Array in JavaScript
  • Check if an Array Contains a Specific Value
  • Insert Item into an Array at a Specific Position
  • Append an Object to an Array in JavaScript
  • Check if a Given Object is an Array
  • Clear Array Contents in JavaScript
  • Add Element to Beginning of Array
  • Remove Duplicates from an Array
  • Merge Two Arrays and Remove Duplicates in JavaScript
  • Sort Array of Objects by Property in JavaScript
  • Create a Two-Dimensional Array in JavaScript
  • Extract Specific Property Values from Objects as an Array
  • Compare Two Arrays for Equality
  • Get a Random Item from an Array in JavaScript
  • Find the Intersection of Two Arrays in JavaScript
  • Chunk an Array into Smaller Sub-arrays
  • Including One JavaScript File Inside Another JavaScript File
  • Get the File Extension from a File Name
  • Check if a Variable is undefined or null in JavaScript
  • JavaScript Program to Set a Default Value for Function Parameters
  • JavaScript Program to Demonstrate Set Operations
  • Generate a Random Number Within a Given Range
  • Retrieve the Current Webpage URL Using JavaScript
  • JavaScript Program to Validate an Email Address
  • Check if Variable is a Function in JavaScript
  • Working with Constants in JavaScript
  • Pass Arguments to setTimeout() in JavaScript
  • Generate a Sequence of Numbers and Characters in JavaScript
  • JavaScript Program to Simulate Function Overloading
  • Implement a Stack Using JavaScript
  • Implement a Queue in JavaScript
  • Check if a Number is a Float or Integer
  • Pass a Function as an Argument in JavaScript
  • Get the Width and Height of an Image in JavaScript
  • Remove All Whitespace from a String
  • Console Log Writer in JavaScript
  • Convert Date Object to Timestamp
  • Determine if a Year is a Leap Year
  • Synchronous Code Execution in JavaScript
  • Convert Years to Days in JavaScript
  • Validate a Name in JavaScript
  • Check Multiples of 3 or 5
  • JavaScript Function to Retrieve Image Dimensions
  • Check if a Value Exists in a Set

Requirements

  • Basic Understanding of JavaScript: Learners should have a fundamental understanding of JavaScript syntax and basic concepts, including variables, loops, and functions.
  • Motivation to Learn and Solve Problems: A willingness to learn, solve challenging problems, and engage with coding exercises will be essential to benefit fully from the course.

Description

JavaScript Interview Coding Questions and Answers (Solution Code with Detailed Explanations)

Are you preparing for a JavaScript coding interview and seeking to achieve a level of mastery that allows you to confidently address challenging, nuanced questions? This course is meticulously crafted to provide you with a profound competitive advantage, irrespective of your current level of expertise.

In this course, you will engage in hands-on practice with a carefully curated set of real-world JavaScript interview questions, enriched with comprehensive hints, step-by-step solutions, and in-depth theoretical explanations. Whether you are an aspiring developer preparing for your initial technical interview or a seasoned professional aiming to refine your problem-solving acumen, this course offers deep insights and practical skills through an extensive range of problems and detailed analytical walkthroughs.

Key Features of This Course:

  • Detailed Hints for Problem Solving: Before delving directly into the solution, you will receive strategic hints designed to enhance your cognitive approach, guiding you towards effective problem-solving independently. These hints are purposefully constructed to bolster your logical reasoning capabilities and ensure that you develop the analytical mindset necessary for complex problem breakdown. The course aims to foster independent critical thinking, encouraging you to dissect questions into modular components.

  • Solution Code with Step-by-Step Explanation: Each question is accompanied by a fully detailed solution, articulated step-by-step to ensure deep conceptual understanding. This pedagogical approach transcends rote memorization of code—rather, it equips you with the rationale behind each line of implementation. You will cultivate the ability to think like a sophisticated JavaScript engineer, an essential skill that will significantly distinguish you from other candidates. The granular dissection of every solution aims to provide a holistic understanding of the underlying concepts, core principles, and design patterns that are prevalent in JavaScript technical interviews.

  • Comprehensive Coverage of Common Interview Questions: This course offers an exhaustive collection of questions frequently posed by hiring managers. It spans fundamental JavaScript concepts, such as closures, promises, and callback functions, extending to advanced algorithmic challenges and data structure intricacies. Additionally, you will encounter nuanced questions that probe your understanding of JavaScript's subtleties and more sophisticated features. Such comprehensive exposure prepares you for the full spectrum of questions you are likely to face during a rigorous technical interview.

  • Mastery of Problem-Solving Methodologies: Beyond merely providing answers, this course places a pronounced emphasis on developing and honing effective problem-solving strategies. You will gain insight into multiple potential approaches to each challenge, along with an analysis of the comparative advantages and limitations inherent to each method. This perspective not only prepares you for interview scenarios but also significantly enhances your overall software development prowess, enabling you to produce cleaner, more efficient, and maintainable code in practical settings.

  • Deep Dive into JavaScript Fundamentals: This course eschews superficial coverage in favor of an in-depth exploration of JavaScript's foundational concepts as well as its advanced features. Mastering these core topics provides the necessary framework to approach even the most challenging interview questions with composure and clarity. We delve into critical subjects such as hoisting, closure behavior, the intricacies of the event loop, and asynchronous programming paradigms to ensure that you are fully equipped for any technical inquiry.

Why This Course Will Benefit You:

  • Confidence Boost for Complex Scenarios: The structured combination of practice questions, strategic hints, and exhaustive solution breakdowns empowers you to approach both straightforward and complex interview scenarios with composure. By internalizing these skills, you will walk into interviews equipped with the tools to address any coding challenge methodically and confidently.

  • Think Like an Expert Developer: This course emphasizes the importance of process over mere results. Gaining a thorough understanding of the rationale—"the why"—behind every solution is crucial to cultivating a comprehensive mastery of JavaScript. You will learn how to systematically deconstruct problems, apply logical frameworks, and think in a manner akin to an experienced software developer. This ability to navigate novel and unfamiliar challenges will be an invaluable asset in both interviews and professional environments.

  • Hands-On, Realistic Practice: Engage with a wide array of challenges that accurately simulate real interview environments. From algorithmic exercises to practical problem-solving drills, every component of this course is tailored to mirror the demands of a technical interview. This experiential approach will refine your technical competencies and prepare you to thrive under the inherent pressures of coding interviews.

  • Effective Coding Patterns and Best Practices: Throughout the course, you will be introduced to essential coding patterns and best practices that will not only enhance the efficiency and readability of your code but also align with what interviewers seek in candidates. Developing a familiarity with these patterns ensures that you write code that is both functionally correct and optimally efficient—characteristics that are crucial in any technical interview or software development role.

  • Application to Real-World Scenarios: The skills and concepts addressed in this course are not confined to interview contexts but are directly transferable to real-world development tasks. By understanding the internal mechanics of JavaScript and consistently applying best practices, you will lay the groundwork for a robust career in software development, well beyond the interview room.

Whether you are aspiring to secure a position at a leading tech company or aiming to enhance your proficiency in JavaScript for your current role, this course offers a comprehensive framework to excel in JavaScript technical interviews. You will emerge equipped with a nuanced understanding that will allow you to tackle problems of varying difficulty, articulate your thought process clearly, and impress prospective employers with insightful and well-formulated solutions.

Take command of your professional development and lay the foundation for success in your software engineering career. Enroll today and begin your journey toward mastering JavaScript interviews!

Who this course is for:

  • Aspiring Developers Preparing for Their First Technical Interview: If you are new to the field of software development and want to land your first job, this course will provide you with a solid foundation to tackle common JavaScript interview questions confidently.
  • Junior to Mid-Level Developers Seeking to Advance Their Skills: Developers with some experience in JavaScript who are looking to strengthen their knowledge, hone their problem-solving abilities, and improve their interview performance will find immense value in the advanced topics and nuanced explanations provided.
  • Career Switchers Moving into JavaScript Development: If you are transitioning from another career or a different technical background, this course will help you bridge the knowledge gap by providing a thorough, practical understanding of JavaScript and common interview patterns.
  • Developers Looking to Refresh Their JavaScript Knowledge: Even experienced developers sometimes need a refresher, especially when preparing for challenging technical interviews. This course will provide an efficient and comprehensive review of JavaScript fundamentals and more advanced concepts, ensuring you are fully prepared.

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