Parallel Wireless Interview Questions and Answers

let, var and const are all used to declare variables in JavaScript, but they differ in their scope and mutability.

• let has block scope and can be reassigned

• var has function scope and can be reassigned

• const has block scope and cannot be reassigned, but its properties can be mutated

Design a database schema for nested comments on a post

• Create a table for posts with a unique ID

• Create a table for comments with a unique ID, post ID, and parent comment ID

• Use foreign keys to link comments to posts and parent comments

• Use a recursive function to retrieve nested comments

Event loop is a mechanism in JavaScript that handles asynchronous operations.

• Event loop continuously checks the call stack and the task queue.

• If the call stack is empty, it takes the first task from the queue and pushes it to the call stack.

• Event loop is responsible for handling callbacks and promises.

• Event loop prevents blocking of the main thread.

A calculator app built using React

• Create a component for the calculator

• Use state to keep track of the input and result

• Implement functions for basic arithmetic operations

• Add buttons for each number and operation

• Display the input and result on the screen

Higher order functions are functions that take other functions as arguments or return functions as their output.

• Higher order functions can be used to create more flexible and reusable code.

• They allow for functions to be composed and combined in various ways.

• Examples of higher order functions include map, filter, and reduce in JavaScript.

• Higher order functions can also be used for currying and partial application.

MVC stands for Model-View-Controller. It is a software design pattern used for developing web applications.

• MVC separates an application into three interconnected components: Model, View, and Controller.

• Model represents the data and business logic of the application.

• View represents the user interface of the application.

• Controller handles the user input and updates the model and view accordingly.

• MVP stands for Model-View-Presenter. It is a variation of MVC pattern.

• In MVP, Prese...read more