Physicswallah Front end Developer Interview Questions and Answers

Q1. What is memoization in react
Ans. 
Memoization is a technique used to optimize performance by storing the results of expensive function calls and returning the cached result when the same inputs occur again.
• Memoization helps to avoid redundant calculations by storing the results of function calls.

• It can be implemented using libraries like 'memo' in React or manually by storing results in a cache.

• Memoization is commonly used in React to optimize renderin...read more
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Q2. Promise vs promise all
Ans. 
Promise is used for asynchronous operations with a single result, while Promise.all is used for handling multiple promises simultaneously.
• Promise is used for handling asynchronous operations with a single result

• Promise.all is used for handling multiple promises simultaneously

• Promise.all waits for all promises to resolve or any one to reject
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Q3. Minimum sum path
Ans. 
Find the path with the minimum sum in a grid from the top-left to the bottom-right corner.
• Use dynamic programming to store minimum sums at each cell.

• Start from the top-left corner and move to the bottom-right.

• At each cell, calculate the minimum sum from the top and left cells.

• Example: For a grid [[1,3,1],[1,5,1],[4,2,1]], the minimum path sum is 7.

• The final cell will contain the minimum sum path value.
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Q4. React Vs Angular
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React is a lightweight library for building user interfaces, while Angular is a full-fledged framework with more features and conventions.
• React is more flexible and allows for more control over the code structure.

• Angular provides more out-of-the-box features like routing, forms, and HTTP client.

• React is easier to learn for beginners due to its simplicity.

• Angular has a steeper learning curve but offers more built-in too...read more
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Q5. In what cases will you use Promise.all
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Promise.all is used to handle multiple promises concurrently and wait for all of them to resolve.
• Use Promise.all when you need to make multiple asynchronous calls and wait for all of them to complete before proceeding.

• It is useful for scenarios like fetching data from multiple APIs and processing them together.

• Example: Promise.all([fetch('url1'), fetch('url2')]).then(responses => { // handle responses })
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Q1. Situational questions
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Q2. Questions related to day to day work
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Api Call with pagination support, Card with button.

Same , Just changed the difficulties