Uber React Js Frontend Developer Interview Questions and Answers

Q1. What is anti pattern in react?
Ans. 
An anti-pattern in React is a common mistake or bad practice that should be avoided.
• Using index as key in lists can cause issues with component re-rendering

• Using setState in a loop can lead to unexpected behavior

• Not using PureComponent or memoization for performance optimization

• Overusing context instead of props drilling can make code harder to maintain
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Q2. Why should we use flux instead of grid and vice versa
Ans. 
Flux is a design pattern for managing data flow in React applications, while Grid is a layout system for organizing content.
• Flux is useful for managing complex data flow in large applications, ensuring data consistency and predictability.

• Grid is useful for creating responsive layouts and organizing content in a visually appealing way.

• Flux helps in maintaining a unidirectional data flow, making it easier to debug and un...read more
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Q3. How to optimize react application
Ans. 
Optimizing a React application involves code splitting, lazy loading, using memoization, minimizing re-renders, and optimizing network requests.
• Implement code splitting to load only necessary code for each route or component.

• Use lazy loading to load components only when they are needed.

• Memoize expensive calculations or functions using useMemo or useCallback.

• Minimize re-renders by using shouldComponentUpdate or React.me...read more
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Not bad it was good.

Easy and medium questions

Q1. What are promises
Ans. 
Promises are objects representing the eventual completion or failure of an asynchronous operation.
• Promises are used to handle asynchronous operations in JavaScript.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() to handle success and .catch() to handle errors.

• Example: fetch() API returns a promise that resolves with the response to a request.
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Q2. How js handle asynchronous codes
Ans. 
JavaScript handles asynchronous codes using callbacks, promises, and async/await.
• Callbacks are functions passed as arguments to another function to be executed later.

• Promises represent the eventual completion (or failure) of an asynchronous operation and allow chaining of multiple asynchronous operations.

• Async/await is a modern way of handling asynchronous code that makes it look synchronous.

• Example: Using setTimeout w...read more
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Q3. Stair climbing leetcode question
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Q1. What are higher order components
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Q2. Diff between state amd props
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Q3. How to pass data from child to parent
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Q4. UseEffect , useState , useMemo hooks
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Q5. How you will optimize the performance of react application
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Q6. Explain context Api
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Q7. What is meant by props drilling
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Q8. What is meant by redux
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Q9. How you implement redux in react js
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Not remember now what they had asked.

Q1. Tell me about yourself?
Ans. 
I am a passionate React Js Frontend Developer with experience in building user-friendly and responsive web applications.
• Experienced in developing web applications using React Js

• Proficient in HTML, CSS, and JavaScript

• Familiar with state management tools like Redux

• Strong understanding of responsive design principles

• Ability to work collaboratively in a team environment
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Q2. What is your expectation ctc ?
Ans. 
My expectation for CTC is competitive based on my experience and skills.
• I am looking for a salary that reflects my expertise in React Js development.

• I expect a compensation package that aligns with industry standards.

• I am open to negotiation based on the overall benefits offered by the company.
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The first round is Hackerrank two algo and one UI test very easy, Second is Fundamentals of JS and React Native one must have a deep understanding of JS to do that I strongly suggest going through Akashay Saini's JS series It'll help and the Third is PS/DS asked some basic A&DS questions can be solved easily with little practice on Leetcode