Trbhi Interview Questions and Answers

Had to check if every opening bracket has a closing pair.

Q1. When Node JS is single-threaded, how it handles multiple requests.
Ans. 
Node JS uses event-driven architecture and non-blocking I/O to handle multiple requests efficiently.
• Node JS uses event loop to handle multiple requests by delegating I/O operations to the system kernel asynchronously.

• It can process multiple requests concurrently without getting blocked by I/O operations.

• Node JS leverages callbacks and Promises to manage asynchronous operations and ensure smooth execution of code.

• Exampl...read more
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Q2. What is callback hell
Ans. 
Callback hell is a situation where multiple nested callbacks make the code difficult to read and maintain.
• Occurs when multiple asynchronous operations are nested within each other

• Leads to deeply nested code which is hard to read and debug

• Can be avoided by using promises, async/await, or libraries like async.js
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Q3. What is currying
Ans. 
Currying is a technique in functional programming where a function with multiple arguments is transformed into a sequence of functions, each taking a single argument.
• Currying helps in partial application of functions.

• It allows for creating reusable functions with fixed parameters.

• Example: const add = a => b => a + b; add(2)(3) returns 5.
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Q4. What is an event loop?
Ans. 
Event loop is a mechanism that allows for asynchronous programming by handling events and callbacks.
• Event loop is a single-threaded mechanism that processes tasks in a non-blocking way.

• It continuously checks the event queue and executes the appropriate callback functions.

• Commonly used in JavaScript for handling asynchronous operations like setTimeout, setInterval, and promises.
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Q5. How does middleware in express.js work?
Ans. 
Middleware in express.js is a function that has access to the request and response objects, and can modify them or terminate the request-response cycle.
• Middleware functions can perform tasks like logging, authentication, error handling, etc.

• Middleware is added using app.use() method before defining routes.

• Middleware functions can also be added locally to specific routes using app.use() before the route handler.

• Example:...read more
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