Yari QualiTech Interview Questions and Answers

Question 1

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Q1. What is redux in reactjs

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Redux is a state management library for JavaScript applications.

Redux helps manage the state of an application in a predictable way
It provides a central store for all the application's state
Actions are dispatched to update the store, and components can subscribe to changes in the store
Redux can be used with React, Angular, and other JavaScript frameworks

Question 2

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JWT tokens are used for authentication and authorization in ReactJS applications.

JWT stands for JSON Web Token
Tokens are generated on the server and sent to the client
Tokens contain encoded information about the user and their permissions
Tokens are stored in local storage or cookies
Tokens are sent with each request to the server for authentication and authorization

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Docker is a platform that allows you to package, distribute, and run applications in isolated containers.

Docker containers are lightweight, portable, and self-sufficient environments that include everything needed to run an application.
Docker uses containerization technology to create and manage containers, which can be easily deployed across different environments.
Docker simplifies the process of building, shipping, and running applications by providing a consistent environm...read more

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Lookup in MongoDB is used to perform a join between two collections.

Lookup is used to combine data from multiple collections in a single query.
It is similar to a SQL join operation.
Lookup requires a local field in the input collection and a foreign field in the from collection.
Example: db.orders.aggregate([{ $lookup: { from: 'products', localField: 'productId', foreignField: '_id', as: 'productDetails' } }])

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Yes, I have deployed multiple applications in AWS.

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Event loop is a mechanism that allows for asynchronous programming by handling and executing events in a loop.

Event loop is a part of the runtime environment in JavaScript.
It manages the execution of multiple tasks by putting them in a queue and processing them one by one.
Event loop allows for non-blocking I/O operations, making the code more efficient and responsive.
Example: setTimeout() function in JavaScript uses the event loop to schedule the execution of a function after...read more