Metafic Reactjs Developer Interview Questions, Process, and Tips

Q1. What is virtual DOM in react?
Ans. 
Virtual DOM is a lightweight copy of the actual DOM used for efficient rendering in React.
• Virtual DOM is a JavaScript object that represents the actual DOM.

• It allows React to update only the necessary parts of the UI, improving performance.

• Changes made to the virtual DOM are compared with the previous version to determine what needs to be updated.

• React then updates the actual DOM with the minimum required changes.

• Virtu...read more
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Q2. Explain UseMemo, UseCallback, UseEffect uses, and lifecycle method in the class component.
Ans. 
Explanation of React hooks and lifecycle methods
• useMemo is used to memoize expensive computations and avoid unnecessary re-renders

• useCallback is used to memoize functions and avoid unnecessary re-renders of child components

• useEffect is used to perform side effects such as fetching data or updating the DOM

• Lifecycle methods in class components are used to manage component state and perform side effects

• ComponentDidMount i...read more
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Q3. Javascript array-based pattern questions dependent on loop, slice, and splice methods
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Q1. Write code for functional component to call an API and show a list from the response (given by the interviewer)
Ans. 
Code for functional component to call API and show list from response
• Use useEffect hook to call API on component mount

• Use useState hook to store API response

• Map through response data to display list

• Handle loading and error states
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Q2. Write down the code from that API to integrate pagination on scrolling
Ans. 
Code for integrating pagination on scrolling in Reactjs API
• Use Intersection Observer API to detect when the user has scrolled to the bottom of the page

• Fetch the next set of data from the server using an API call

• Update the state with the new data and render it on the page
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Logic test and js based coding questions for 45-60 mins

Q1. How would be dealing with an issue which was caused due to others?
Ans. 
I would approach the issue by identifying the root cause and collaborating with the team to find a solution.
• Identify the root cause of the issue

• Collaborate with the team to find a solution

• Communicate effectively with all parties involved

• Take ownership of the issue and work towards a resolution

• Document the issue and the steps taken to resolve it
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Q2. Where would you see yourself in next 3 years?
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