It's useful for merging arrays or creating copies (as seen in action in question #19). You can use the filter method to create a new array with only numbers. Then, use return Math.max(...numbers) to find the largest number. Here we’re using the spread operator again to provide the values of the array as individual parameters of the Math.max method. In JavaScript, hoisting is a mechanism where variable and function declarations are moved to the top of their containing scope during the compilation phase, before the code is executed.

August 5, 2025 - These Top 50 coding questions and answers will help you to improve your coding concept in JavaScript. If you're a beginner and want to gather some real-time coding examples, then start here. This section will help you understand the fundamentals and solve simple coding problems. This code splits the string into an array of characters using the split() method, reverses the array, and joins it back into a string using the join() method.

March 28, 2025 - The questions are arranged so the patterns build on each other: closures appear in Debounce, Throttle, Once, and Memoize; recursion appears in Flatten, Deep Equal, Deep Clone, and getElementsByClassName; promise composition appears in Promise.all, Promise.allSettled, and is a common follow-up to Event Emitter (replacing callbacks with promises). Practice each one on the linked GreatFrontEnd page; the IDE runs the same kinds of test cases real interviewers use, so edge cases surface before the interview does. If you'd like to go beyond these 18 questions, check out our open-source GitHub repo featuring +190 JavaScript interview questions with detailed answers and test cases.

List of 1000 JavaScript Interview Questions. Contribute to sudheerj/javascript-interview-questions development by creating an account on GitHub.

October 7, 2020 - What Makes Javascript Weird...and ... visual code examples. What the heck is the event loop anyway? | Philip Roberts | JSConf EU - One of the most famous JavaScript videos recently. He explains how JavaScript works "Behind the scenes" (how the event loop works). Of course, this is only some of the resources on the subject. There are many other resources to learn from. So are you ready to get your mind blow away (from JavaScript question)? Notice 1!: To each question, there is an answer with an ...

January 5, 2026 - 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 ...

August 21, 2025 - The right-hand side [b, a] creates a new array with the values of b and a, and the destructuring assignment [a, b] assigns these values back to a and b respectively. ... Thanks for reading this article! ... I’ve recently published my free book in preparing for JavaScript interviews. The book contains 100 frequently asked JavaScript interview questions with answers.

May 20, 2026 - 50+ JavaScript interview questions for 2026, with code examples and answers curated by ex-FAANG interviewers. Covers ES2025: immutable array methods, new Set methods (union/intersection), structuredClone, and modern async patterns.

When managers ask this question, they are looking for the candidate’s basic understanding of JavaScript. They assess their understanding of basic syntax along with problem-solving skills. This also helps evaluate the candidate’s coding style and attention to detail. I would take two parameters and the following function can be used to calculate the sum of any 2 numbers that are passed as arguments. ... A hiring manager asks this question to analyze the candidate’s ability to write clear and efficient code.

If you are a member of one of my premium classes, you can jump into the #JavaScript30 room in our Slack channel. Yes! There are probably 100 different ways to solve each of these exercises, if your answer doesn't line up with mine, it means you did a really good job at trying to figure it out yourself. My answers are by no means the best answers - just a single way of doing it.

November 10, 2019 - The code above will output 5 even though it seems as if the variable was declared within a function and can't be accessed outside of it. This is because ... But b is not declared anywhere in the function with var so it is set equal to 5 in the global scope. Having Tech or Coding Interview? Check 👉 179 JavaScript Interview Questions ... 🤖 Having Machine Learning & DS Interview? Check MLStack.Cafe - 1704 Data Science & ML Interview Questions & Answers!Having ML & DS Interview?

The test contains 25 questions and there is no time limit. The test is not official, it's just a nice way to see how much you know, or don't know, about JavaScript. You will get 1 point for each correct answer. At the end of the Quiz, your total score will be displayed.

Practice JavaScript online with our set of coding problems selected for beginners. Solve these JavaScript coding problems and prepare for your interviews.

From 80's BASIC to JavaScript · What is ASCII? Importance of code indentation · How to write clean code? Explaining binary numbers using light bulbs · Charles Babbage facts for kids · Avoid these top 10 coding mistakes · About ASCII and Unicode · 12 questions answered about coding ·

Prototypal inheritance is an important ... within a JavaScript application. By asking this question, an interviewer provides the opportunity for you to show your knowledge and explain the importance of this key concept. In your answer, note that prototypal inheritance provides benefits when creating and using objects within your code, including ...

3 weeks ago - Prepare with top Node.js interview questions for 2026 - event loop, async/await, streams, Express, security, performance, and system design for all levels.

Sharpen your JavaScript skills with 500+ coding challenges and compete with other challengers to stay on the leaderboard. Available for all levels. Start Now.

September 10, 2024 - Learning tip: Practice core JavaScript skills in a realistic cloud IDE before your next interview for assessment—Mastering Algorithms and Data Structures in JavaScript in CodeSignal Learn helps you do just that. Question: Write a JavaScript function checkDataTypes that takes three parameters and returns an array containing the data type of each parameter.