KocharTech Mern Full Stack Developer Interview Questions, Process, and Tips

Variables in JavaScript are used to store data values.

• Variables are declared using the 'var', 'let', or 'const' keywords.

• Variables can store different types of data such as numbers, strings, arrays, objects, etc.

• Variables can be reassigned with new values.

• Variables are case-sensitive.

• Example: var x = 5; let name = 'John'; const PI = 3.14;

The 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 functions that need to be executed.

• If the call stack is empty, the event loop will take a function from the callback queue and push it onto...read more

Event emitter in Node.js is a module that allows objects to emit and listen for events.

• Event emitter is a built-in module in Node.js

• It allows objects to emit named events that cause Function objects to be called

• Example: const EventEmitter = require('events');

• Example: const myEmitter = new EventEmitter();

Aggregation in MongoDB is a framework for performing data processing operations on documents within a collection.

• Aggregation pipeline stages allow for data transformation, filtering, sorting, grouping, and more

• Operators like $match, $group, $project, $sort, $limit, $skip are commonly used in aggregation

• Aggregation results can be output to a new collection, returned inline, or used for further processing