Dimaag-AI Mern Full Stack Developer Interview Questions and Answers

Q1. What is differnce between class and functional component
Ans. 
Class components are ES6 classes that extend from React.Component and have a render method, while functional components are simple functions that return JSX.
• Class components are more feature-rich and have access to lifecycle methods like componentDidMount, componentDidUpdate, etc.

• Functional components are simpler and easier to read, especially for simple UI components.

• Functional components can use React Hooks to manage...read more
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Q2. Write a basic function component
Ans. 
A basic function component in React
• Create a function component using the 'function' keyword

• Return JSX elements within the component function

• Example: const MyComponent = () => { return

  Hello World!
  ; }
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Q1. What is virtual DOM?
Ans. 
Virtual DOM is a lightweight copy of the actual DOM that allows for efficient updates and rendering in web applications.
• Virtual DOM is a concept used in frameworks like React to improve performance by minimizing direct manipulation of the actual DOM.

• When changes are made to the virtual DOM, a comparison is done with the actual DOM to identify the minimal number of updates needed.

• This approach reduces the number of DOM ...read more
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Q2. What is foriegn Key SQL?
Ans. 
Foreign key in SQL is a field in a table that is a primary key in another table, establishing a relationship between the two tables.
• A foreign key constraint ensures referential integrity between two related tables.

• It helps maintain consistency and avoid orphan records.

• Example: In a database with tables 'orders' and 'customers', the 'customer_id' in 'orders' table can be a foreign key referencing the 'id' column in 'cus
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Q1. What is props
Ans. 
Props are read-only properties that are passed from a parent component to a child component in React.
• Props allow data to be passed down the component tree.

• Props are immutable and cannot be changed by the child component.

• Props are accessed in the child component using this.props.
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Q2. What is Good feedback you ever got in during you development period.
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Q1. What is error handling middleware?
Ans. 
Error handling middleware is a function that processes errors in an Express application.
• Error handling middleware is defined with four parameters: err, req, res, and next.

• It is used to catch errors that occur during the execution of route handlers or other middleware functions.

• It is typically defined at the end of the middleware chain with app.use() and has a signature like (err, req, res, next) => {...}.

• Example: app.u...read more
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Good one hour arrays linbklist strings

Q1. Which one you choose mongo vs mysql and why
Ans. 
I would choose MongoDB for its flexibility and scalability in handling unstructured data.
• MongoDB is a NoSQL database, making it easier to work with unstructured data compared to MySQL which is a relational database.

• MongoDB is highly scalable and can handle large amounts of data and high traffic loads.

• MongoDB is a good choice for applications that require frequent updates and real-time analytics.

• MySQL is a better choice...read more
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Oops,Function ,and basic concept of cloud

Q1. Tell me about your self. Why are you interested in this company/role?
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Q2. Do you have any questions for us
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Q3. Greatest professional achievement so far
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Q4. Short team and long team goals
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Q5. Your strength & weakness
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Q1. Was asking in-depth about my past company's projects
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Q2. Was asking in-depth in my technology which i mentioned in resume
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