devtools.tech | The only way to prepare for frontend interviews

Devtools Tech

Team Devtools Tech Official Profile

Certificates

Certificate for JavaScript Memory and Garbage Collection

JavaScript Memory and Garbage Collection

Issued 6 October 2026

Company Structure Validator

1,788

Compare Semantic Versions

1,304

Implement a Timeout-Based API Wrapper with Optional Retry

2,861

Measure Function Execution Time

1,982

Breadcrumb Chain Problem

3,408

Build an API Client

3,267

Function Call Counter

2,825

Count Total Comments

4,045

String Compression and Decompression

4,065

What would be the return value (if any)?

9,610

Implement Event-Driven Key-Value Store

2,751

Implement Promisify Polyfill

2,851

How to create analytics SDK in JavaScript?

6,911

How to group array of objects by key?

7,377

How to implement custom Array.prototype.square method?

5,617

Build a Virtual DOM to actual HTML DOM Convertor | DOM Renderer

6,773

How to implement a chainable Add function to calculate the sum of numbers?

7,415

How to implement Array.isArray? JavaScript Interview Question | Array Polyfills

7,624

How to implement Array.prototype.filter? JavaScript Interview Question | Array Polyfills

5,941

How to implement an Asynchronous Task Runner with Concurrency Control? Rippling Frontend Interview Question

7,567

How to implement auto-retry Promise on Rejection? | Frontend Problem Sovling

6,783

How to implement a prize calculator? JavaScript Interview Question

4,787

Implement Count By | JavaScript Problem Solving

3,602

How to implement feature flag functionality? Atlassian Frontend Interview Question

10,747

Implement a Credit Card Masker | Klarna Frontend Interview Question | JavaScript

6,852

Write a function to return the count of numbers in an Array | MakeMyTrip Frontend Interview Question

6,560

How to implement a function to convert a string input into an object? | Razorpay Interview Question | JavaScript

7,680

How to find the most frequent word in a paragraph? Frontend Problem Solving | JavaScript

5,603

Implement a function that returns the number of parameters expected by a function in JavaScript

5,149

How to implement pipe utility? | Razorpay Interview Question | JavaScript

6,584