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CoderPad
coderpad.io › online-coding-tests › javascript
Online JavaScript Coding Test - 15+ questions to screen candidates
January 5, 2024 - Developers' JavaScript skills can be assessed during coding interviews with the help of the provided JavaScript online tests below.
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W3Schools
w3schools.com › js › js_quiz.asp
JavaScript Quiz Test
You can test your JavaScript skills with W3Schools' Quiz. The test contains 25 questions and there is no time limit.
Discussions

[AskJS] Is JavaScript good enough for coding interviews?
Depends on the position. If they're interviewing for frontend it definitely should be. For backend is going to depend on what they happen to use. For your first job they may or may not expect you to be familiar with their language of choice and instead have you writing pseudo code during the interview. More on reddit.com
🌐 r/javascript
18
18
November 6, 2021
Javascript coding interview/test

Any tips on what kinda things would come up?

  • arrays

  • objects

  • functions

  • inheritance

  • scope

  • closure

  • ajax/xmlhttprequest

  • unit testing

  • node.js

  • DOM

  • favorite tools

  • code organization

  • thoughts on build tools/dependencies

  • accessibility

  • security

  • events

  • event loop

  • promises

  • callbacks

  • A/B testing

  • thoughts on frameworks: angular, react, ember

  • thoughts on code extending utilities: lodash, backbone, jquery, express

  • thoughts on vanilla js

If I were interviewing you I would start with abstract subjects I would expect experts to know and then gradually dial back my questions until I can pinpoint your approximate level of expertise. I wouldn't ask anything super specific, because that is what references are for and I am not trying to be an ass. I also wouldn't ask you to solve any code problems, but I might ask you to demonstrate an answer with code if words aren't enough for me to understand your position. A good interviewer wants to help the candidates relax and feel comfortable because they get much better (and honest) answers to consider. Not everybody is a good interview though.

More on reddit.com
🌐 r/javascript
7
4
September 29, 2013
Just had a Javascript test for a position and not sure about this question. Can anyone give an answer and explanation?
I dislike these kinds of tests in interviews, but in the interests of a good and useful discussion here... JavaScript is not multi-threaded. No way, no how (setting aside WebWorkers and what-not). So the setInterval call says, "make a note to yourself to run this function no less than every 1,000 milliseconds, or one second." Then you are told that the loop takes four seconds to run. But during those four seconds, it never cedes control of the single execution thread. So func1 is still sitting there, waiting to be executed. When the loop completes, the JavaScript engine looks around to see if there's anything to do and yes, func1 is overdue by three seconds. So it executes func1 once and then queues it up to be executed no less than 1,000 milliseconds later. UPDATE: four times right after each other, because four seconds had passed. So the answer is, it doesn't execute at all during those four seconds that JavaScript is executing the loop. Normally I try to use these opportunities to pimp my JavaScript book, but speaking very frankly, I avoided this topic entirely and it can't help you :-( More on reddit.com
🌐 r/javascript
68
30
March 21, 2013
Today's javascript interview questions

Makes me feel better (or worse 🤔) as I go into an interview tomorrow haha. Thanks for sharing.

More on reddit.com
🌐 r/webdev
42
44
November 27, 2017
People also ask

How to empty an array in JavaScript?
**Method 1** ```javascript arrayList = []; ``` Above code will set the variable `arrayList` to a new empty array. This is recommended if you don't have **references to the original array** `arrayList` anywhere else because It will actually create a new empty array. You should be careful with this way of empty the array, because if you have referenced this array from another variable, then the original reference array will remain unchanged, Only use this way if you have only referenced the array by its original variable `arrayList`. For Instance: ```javascript var arrayList = ['a', 'b', 'c'
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fullstack.cafe
fullstack.cafe › blog › javascript-code-interview-questions
25+ JavaScript Coding Interview Questions (SOLVED with CODE) | ...
FizzBuzz Challenge
Check out this version of FizzBuzz: ```js for (let i = 1; i <= 100; i++) { let f = i % 3 == 0, b = i % 5 == 0; console.log(f ? (b ? 'FizzBuzz' : 'Fizz') : b ? 'Buzz' : i); } ```
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fullstack.cafe
fullstack.cafe › blog › javascript-code-interview-questions
25+ JavaScript Coding Interview Questions (SOLVED with CODE) | ...
How to check if an object is an array or not? Provide some code.
> The best way to find whether an object is instance of a particular class or not using `toString` method from `Object.prototype` ```javascript var arrayList = [1 , 2, 3]; ``` One of the best use cases of type checking of an object is when we do method overloading in JavaScript. For understanding this let say we have a method called `greet` which take one single string and also a list of string, so making our `greet` method workable in both situation we need to know what kind of parameter is being passed, is it single value or list of value? ```javascript function greet(param) { if() {
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fullstack.cafe
fullstack.cafe › blog › javascript-code-interview-questions
25+ JavaScript Coding Interview Questions (SOLVED with CODE) | ...
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InterviewBit
interviewbit.com › javascript-interview-questions
100+ JavaScript Interview Questions and Answers (2026) - InterviewBit
Explore 100+ JavaScript interview questions and answers for 2026, covering basics to advanced topics like closures, hoisting, promises, DOM, and ES6.
Published   January 26, 2026
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GeeksforGeeks
geeksforgeeks.org › javascript › javascript-coding-questions-and-answers
JavaScript Coding Questions and Answers - GeeksforGeeks
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.
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GitHub
github.com › sudheerj › javascript-interview-questions
GitHub - sudheerj/javascript-interview-questions: List of 1000 JavaScript Interview Questions · GitHub
Easier testing: Since output depends ... to test. Predictability: No hidden side effects make behavior easier to reason about. Immutability: Pure functions align with ES6 best practices, such as preferring const over let, supporting safer and more maintainable code. No side effects: Reduces bugs related to shared state or mutation. ... The let keyword in JavaScript is used to ...
Author   sudheerj
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Keka
keka.com › javascript-coding-interview-questions-and-answers
JavaScript Coding Interview Questions and Answers List | Keka
Collaboration and team fit: Adapting ... code reviews, and cross-functional teamwork. Problem ownership: Taking responsibility for debugging, testing, and delivering working solutions under deadlines. Adaptability: Staying open to new frameworks, shifting requirements, and evolving project needs. These top 50 JavaScript interview questions and answers ...
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TestDome
testdome.com › tests › javascript-online-test › 14
JavaScript Online Test | TestDome
The assessment includes work-sample tasks such as: Handling user events and manipulating DOM to build responsive web pages. Using classes, objects, and closures to write maintainable and reusable code.
Find elsewhere
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GreatFrontEnd
greatfrontend.com › questions › javascript-interview-questions
JavaScript Interview Questions | Solutions by Ex-FAANG interviewers
480+ most important JavaScript interview questions, from library APIs and utility functions to algorithms and UI components. Questions and solutions by ex-interviewers · Comprehensive test cases · Code in browser · Search questions · Sort by · JavaScript functions ·
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Toptal
toptal.com › javascript › interview-questions
Top 37 Technical JavaScript Interview Questions & Answers [2025] | Toptal®
OK, fine. But if 3 is being logged after a delay of 0 msecs, doesn’t that mean that it is being logged right away? And, if so, shouldn’t it be logged before 4, since 4 is being logged by a later line of code? The answer has to do with properly understanding JavaScript events and timing.
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FullStack.Cafe
fullstack.cafe › blog › javascript-code-interview-questions
25+ JavaScript Coding Interview Questions (SOLVED with CODE) | FullStack.Cafe
As an asynchronous event-driven JavaScript runtime, Node.js is designed to build scalable network applications. Follow along to refresh your knowledge and explore the 52 most frequently asked and advanced Node JS Interview Questions and Answers every... ... Dependency Injection is most useful when you're aiming for code reuse, versatility and robustness to changes in your problem domain. DI is also useful for decoupling your system. DI also allows easier unit testing ...
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Tests4geeks
tests4geeks.com › javascript-online-test
JavaScript Online Test (20 Questions, 35 Mins) - Tests4Geeks
You can automatically assess the programming aptitude of prospective candidates using our JavaScript online test. This quiz consists of 20 questions written and reviewed by a team of veteran JavaScript developers. It covers a wide spectrum of JavaScript language knowledge and provides an accurate ...
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Roadmap
roadmap.sh › questions › javascript-coding
Top 80 JavaScript Coding Interview Questions and Answers
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.
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MDN Web Docs
developer.mozilla.org › en-US › docs › Learn_web_development › Core › Scripting › Test_your_skills
Test your skills: JavaScript - Learn web development | MDN
August 18, 2025 - This page lists JavaScript tests you can try so you can verify if you've understood the content in this module. ... The aim of this skill test is to help you assess whether you've understood our Arrays article. ... The aim of this skill test is to help you assess whether you've understood our Making decisions in your code — conditionals article.
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CodeChef
codechef.com › skill-test › javascript
JavaScript Online Test & Quiz
Take the JavaScript Online Test & Quiz assessment to evaluate practical skills effectively using a set of well-designed, high-quality questions.
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Codinn
codinn.dev › tricky-javascript › es6789-code-snippets-interview-questions
Tricky Javascript Code Snippets Questions Asked in the Interview (es6/es7/es8/es9)
Prepare for your next 2025 Javascript Coding Interview Questions with these tricky code snippets. Covering ES6/ES7/ES8/ES9 syntax and features, this article provides examples and explanations to help you ace your interview.
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DevSkiller
devskiller.com › home › coding tests › javascript
JavaScript coding questions for technical screening - DevSkiller.com
3 weeks ago - Identify the best JavaScript developers with DevSkiller JavaScript coding questions powered by RealLifeTesting™ methodology.
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Built In
builtin.com › software-engineering-perspectives › javascript-interview-questions
55 Top JavaScript Interview Questions with Example Answers | Built In
Use this list of 55 common JavaScript interview questions and answers to help practice your coding fundamentals and ace your next interview.
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CodeInterview
codeinterview.io › home › 30 javascript coding interview questions for developers
30 JavaScript Coding Interview Questions for Developers
September 2, 2024 - Analyze the below code snippet and advise what will be the output: const person = { firstName: "Helen", lastName: "Ryan", getFullName: function () { return this.firstName + " " + this.lastName; }, }; console.log(person.getFullName()); ... setTimeout(function () { console.log("This will be executed after 3 seconds"); }, 3000); clearTimeout(); ... When designing interview questions for mid-level JavaScript developers, you should prepare challenges to test the understanding of advanced JavaScript concepts and problem-solving skills.
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Practice Aptitude Tests
practiceaptitudetests.com › programming › javascript-tests
JavaScript Assessments: Practice Questions (2026)
September 2, 2024 - Which of the following JavaScript expressions will correctly compare two values to determine strict equality? ... In the context of asynchronous operations in JavaScript, what is the primary purpose of using async/await?