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JavaScript online test: Top 50 data structures interview questions


Data structures and algorithm questions will play a vital role if you’re screening candidates for Java-based roles. When it comes to hiring JavaScript developers through JavaScript online tests, the quality of your data structures interview questions will help you filter out the best candidates.

A thorough understanding of data structures and algorithms is one of the main strengths of a JavaScript developer. In this blog post, we have compiled a list of JavaScript data structures interview questions to help you hire the best developers via JavaScript online test.

10 basic data structures questions to ask in JavaScript online tests 

What is data structure
  1. What is data structure?

Definition, storage, and retrieval of data using a structured and systematic framework is what data structure is all about. Different types of data can be stored in a data structure.

  1. What are various data structures available?

The commonly used data structures include lists, arrays, stacks, queues, graphs, trees, etc.

  1. What is linear data structure?

Linear data structures have sequentially arranged data elements. Lists and arrays are examples of linear data structures.

  1. What are common operations that can be performed on a data structure?

The five common operations performed on any data structure are the following: Insertion, Deletion, Traversal, Searching, and Sorting.

  1. What is a linked list?

In a linked list, the items in the list are linked through links, which can be either pointers or references.

  1. What are stacks?

Stacks are Abstract Data Types used to hold and retrieve values in the Last In First Out order in data structures.

  1. What is an array?

An array is a container for storing a fixed number of items, and the items inside should also be the same type. 

  1. What is an algorithm?

Algorithms are sets of ordered steps that, when executed, solve problems.

  1. Which method can be used to add items from another set to the current set?

To add items from another set into the current set, the update() method can be used.

  1. Which method can be used to remove an item from a list?

There are at least three ways to remove elements from a list: using the remove() method, using the pop() method, or using the del operator.

40 intermediate to advanced-level data structures questions for JavaScript online test

Importance of data structure

A data structure is nothing but a specialized way of organizing and storing data in a computer system. This allows for more efficient ways of handling data as compared to storing data just sequentially.  With the help of data structures and algorithms, we can better understand the nature of a problem and arrive at an optimum solution. 

We have curated a list of 40 questions that you can ask your JavaScript candidates to evaluate their expertise in data structure. 

  1. What is the working of LIFO?

  2. What are multidimensional arrays?

  3. Are linked lists Linear or non-linear data structures?

  4. What is a binary search tree?

  5. What is the meaning of FIFO?

  6. What is the difference between void and null in data structures?

  7. What is dynamic memory management?

  8. What are push and pop operations in data structures?

  9. How is a variable stored in memory when using data structures?

  10. What is merge sort?

  11. Why should Heap be used over a stack?

  12. What is the meaning of data abstraction?

  13. What is the meaning of a postfix expression in data structures?

  14. What is the working of a selection sort?

  15. What are signed numbers in data structures?

  16. What are the minimum nodes binary trees can have?

  17. What data structures make use of pointers?

  18. What is the use of dynamic data structures?

  19. What is a priority queue?

  20. Pointers allocate memory for data storage. True or False?

  21. What is the meaning of deque?

  22. State the difference between linear and non-linear data structures.

  23. What is the meaning of an AVL tree?

  24. How does Huffman’s algorithm work?

  25. What are recursive algorithms?

  26. How does bubble sort work?

  27. Which is the fastest sorting algorithm available?

  28. Where are tree data structures used?

  29. What are the data structures that are used in graphs?

  30. What are the data structures that are used in DFS and BFS algorithms?

  31. What are the time complexities of linear search and binary search?

  32. Where are multi-linked data structures used?

  33. What is the method used for inorder traversal in trees?

  34. What is the working of post-order traversal in trees?

  35. What are the disadvantages of implementing queues using arrays?

  36. How can elements be inserted in the circular queue?

  37. What is the use of void pointers?

  38. What is the meaning of the stack overflow condition?

  39. What is interpolation search technique?

  40. How does quicksort work?

Your data can be efficiently managed, organized, and represented only if your data structure is effective. You can definitely include these questions while you interview your next JavaScript developer.

How to hire top developers via online JavaScript test

Hiring the best JavaScript developers for your company can be difficult, but there are two simple ways to ensure you make the right decision. 

When you start sourcing candidates, you should ask them to complete an initial skills assessment that includes a JavaScript skills test. Once you’ve narrowed down your candidate list with the skills assessment results, ask your remaining applicants fundamental JavaScript data structure interview questions to evaluate them further.

Skills-based hiring is the future and you, as a recruiter, can use online JavaScript tests to make data-driven hiring decisions. Pre-employment assessments along with the above-mentioned JavaScript data structure interview questions will help you hire top JavaScript candidates in days. 

Apart from offering the obvious advantage of focusing on skills, pre-employment JavaScript online tests help you eliminate hiring biases that traditional CV-based recruitment practices fail to address. By removing the over-emphasis on education and degrees, pre-employment tests help you unlock access to a vast pool of global remote talent.

With TestGorilla, you can build a complete pre-employment assessment for your candidates using up to five tests from our test library as well as any custom questions you want to add. Our data-driven online JavaScript tests help recruiters hire top-quality JavaScript developers for their companies while mitigating hiring managers’ unconscious biases.

We recommend using a selection of the following tests to identify and hire the best JavaScript developer candidates.

JavaScript (coding): data structures & objects test

To evaluate your JavaScript developer’s knowledge about data structures, you should give them TestGorilla’s JavaScript (coding): data structures & objects test. In this test, the candidates will have 30 minutes to implement a data structure that meets the given requirements. This will also evaluate your candidate’s object-oriented programming skills. You can also combine this test with other tests such as the jQuery test and the JavaScript (coding) test.

Cognitive ability test

To evaluate a candidate better, choose at least one of the Cognitive Ability tests from our vast test library. For JavaScript developer candidates, we suggest at least one of the following.

  • The Problem-Solving test is a reliable way to evaluate your JavaScript candidates’ ability to define problems and analyze data points to offer solutions

  • Our Attention to Detail (textual) test assesses candidates’ ability to pay attention to textual details whilst working with and processing information

  • Use TestGorilla’s Critical Thinking test to identify applicants who have sharp analytical skills

A personality and culture test

  • Give your JavaScript candidates a Culture Add test to assess how their values align with your company’s

  • The Enneagram test maps your JavaScript candidates’ personalities in a nine-pointed diagram that describes their core beliefs and worldviews

  • TestGorilla’s innovative Motivation test can help you identify JavaScript developers whose expectations align with the role you’re offering

  • Use the 16 Types personality test to understand your JavaScript candidates’ energy sources, lifestyle preferences, decision-making, and information-processing strategies

  • The Big 5 (OCEAN) test will help you evaluate your candidates’ openness, conscientiousness, extroversion, agreeableness, and emotional stability

  • For a deeper understanding of how your candidates express emotions, use the DISC test

Once you’ve built a complete skills assessment, inviting candidates is easy. Sit back and wait for the results to come in, and send reminders if you need to.

Hiring JavaScript developers made easy with TestGorilla

Hire JavaScript developers with pre-employment test

Hiring the best JavaScript developers can be an expensive and time-consuming affair as thousands of companies compete to hire from the tiny pool of high-quality, experienced JavaScript developers. 

The main challenge while hiring quality developers will always be to differentiate between good developers and expert developers. The inherent bias involved in traditional, CV-based hiring practices is another challenge recruiters face.

Surveys suggest recruiting developers with the right skills will be one of the biggest business challenges in 2022. In this case, skills-based hiring is the best solution that organizations can adopt.

TestGorilla offers you world-class, pre-employment assessments to vet candidates effectively. Our data-driven approach provides you with greater insight into a candidate’s ability. Don’t let the CV speak for your candidates anymore. Save valuable time by letting our assessments do the hard work for you.

If you’re a hiring manager or a recruiting professional looking to update your hiring practices, try TestGorilla’s services today. Sign up for free or choose a pricing plan that works for you. Speak to our sales team today and hire the best JavaScript developers in days.


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