Colan Infotech Front end Developer Interview Questions and Answers

Q1. Create a Todo app
Ans. 
A simple Todo app to manage tasks and deadlines
• Create a form to add new tasks

• Display a list of tasks with checkboxes to mark as complete

• Include options to edit or delete tasks

• Implement functionality to mark tasks as complete or incomplete

• Add a feature to filter tasks by status (completed/incomplete)
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Q2. Lifecycle methods
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Q1. React Hooks and Project experience
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Q1. Performance Optimization Techniques
Ans. 
Performance optimization techniques for React JS frontend development
• Use React.memo for optimizing functional components

• Avoid unnecessary re-renders by using shouldComponentUpdate or PureComponent for class components

• Implement code splitting to reduce initial load time

• Use lazy loading for components that are not immediately needed

• Optimize images and assets for faster loading times

• Minimize the use of inline styles and u...read more
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Q2. Lazy Loading and other ques related to that
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Q1. General HR Interview
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Decent questions asked in the online mcq test

Q1. Redux vs context API
Ans. 
Redux is a predictable state container for JavaScript apps, while Context API is a feature in React for passing data through the component tree.
• Redux is more suitable for larger applications with complex state management needs.

• Context API is simpler to use and is built into React, reducing the need for additional libraries.

• Redux provides a single source of truth for the application state, making it easier to debug and ...read more
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Given the task to complete page design.

Q1. Explain event Loop
Ans. 
Event loop is a mechanism in JavaScript that allows for asynchronous operations to be executed in a non-blocking way.
• Event loop is responsible for handling asynchronous operations in JavaScript.

• It continuously checks the call stack and the callback queue to see if there are any tasks to be executed.

• Tasks from the callback queue are moved to the call stack for execution when the call stack is empty.

• Event loop ensures th...read more
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Q2. Explain React Hooks
Ans. 
React Hooks are functions that let you use state and other React features without writing a class.
• React Hooks were introduced in React 16.8.

• They allow you to use state and other React features in functional components.

• Some commonly used React Hooks are useState, useEffect, useContext, etc.

• Hooks are more readable and easier to maintain compared to class components.
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Q1. Create a Todo app
Ans. 
A simple Todo app to manage tasks and deadlines
• Create a form to add new tasks

• Display a list of tasks with checkboxes to mark as complete

• Include options to edit or delete tasks

• Implement functionality to mark tasks as complete or incomplete

• Add a feature to filter tasks by status (completed/incomplete)
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Q2. Lifecycle methods
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Focused on JS questions

Q1. React concept explain
Ans. 
React is a JavaScript library for building user interfaces.
• React is a declarative, efficient, and flexible JavaScript library for building user interfaces.

• It allows developers to create reusable UI components.

• React uses a virtual DOM to improve performance by only updating the necessary parts of the actual DOM.

• React follows a unidirectional data flow, making it easier to understand how data changes over time.

• React can ...read more
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