REDVision Global Technologies Mern Full Stack Developer Interview Questions and Answers

Node.js achieves asynchronous behavior through event-driven architecture and non-blocking I/O operations.

• Node.js uses event-driven architecture to handle asynchronous operations.

• It utilizes non-blocking I/O operations to allow multiple operations to be executed concurrently.

• Node.js uses callbacks, promises, and async/await to manage asynchronous code execution.

• Example: Using callbacks in Node.js to handle asynchronous

Lookup in MongoDB is used to perform a left outer join to retrieve documents from another collection.

• Lookup is used to combine data from two collections based on a common field.

• It is similar to a SQL join operation.

• Lookup is used in aggregation pipelines to fetch related documents from another collection.

• Example: db.collection.aggregate([{ $lookup: { from: 'anotherCollection', localField: 'field', foreignField: 'field'