Toptal Senior Software Engineer Interview Questions and Answers

Q1. Asked to write a program to check whether string is valid or not. String consists of only three kind of special characters "(), [], {}". We need to return true if all special characters are in correct for...read more
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Q2. What is useRef hook used for?
Ans. 
useRef hook is used to persist a mutable value across renders without causing a re-render.
• Used to store mutable values that do not trigger re-renders.

• Commonly used for accessing DOM elements or storing previous values.

• Does not cause a re-render when the value changes.
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Q3. What are the best practices to avoid rerenders and to improve performance
Ans. 
Use memoization, virtual DOM, and shouldComponentUpdate to avoid unnecessary rerenders and improve performance.
• Implement memoization to store the result of expensive function calls and avoid recalculating them.

• Use virtual DOM to efficiently update only the parts of the UI that have changed.

• Override shouldComponentUpdate to prevent unnecessary rerenders by comparing current and next props/state.
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Q4. What are callbacks, Promises, async await
Ans. 
Callbacks, Promises, async await are asynchronous programming concepts in JavaScript.
• Callbacks are functions passed as arguments to another function to be executed later.

• Promises are objects representing the eventual completion or failure of an asynchronous operation.

• async await is a syntax for writing asynchronous code that looks synchronous, making it easier to read and maintain.

• Example: Using a callback to handle th...read more
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Q1. DS and algorithm questions
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Q1. IOS /Skillset questions some tricky questions
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Q1. Personality and Compensation discussion
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Basic questions you can practice becoz time is less

Coding questions include simple moderate tough

Q1. It was tricky like Java hybris developer
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Q2. Questionz about hybris model the work I have done
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Aptitude,reasoning and 2 coding questions

Q1. In first round mixed question were asked from web api and angular. Web api - Difference between post vs put. What is Idempotency? Angular- Difference between ngOnInit vs constructor. What is view encap...read more
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Q1. Technical question from my tech stack.
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Prepare moderate DSA questions on list, queue map

Q1. Explain what project you are working on and springboot microservices questions
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Mental ability, reasoning and matching

Q1. Python, db and UI
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Q1. Throttling, Box-sizing, diff between flex and grid
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Leetcode basic and medium problems of
stack & link list and array

Q1. Basic information , about collage and company
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Q2. Why you want to join our company
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