Interview Questions and Answers

Event Loop in JavaScript manages asynchronous operations by executing callback functions in a non-blocking way.

• Event Loop continuously checks the call stack and the callback queue.

• It moves tasks from the callback queue to the call stack when the call stack is empty.

• This allows JavaScript to handle asynchronous operations without blocking the main thread.

• Example: setTimeout() function adds a task to the callback queue after a specified delay.

SQL joins are used to combine data from two or more tables based on a related column.

• There are four types of SQL joins: inner join, left join, right join, and full outer join.

• Inner join returns only the matching rows from both tables.

• Left join returns all the rows from the left table and matching rows from the right table.

• Right join returns all the rows from the right table and matching rows from the left table.

• Full outer join returns all the rows from both tables, with NULL ...read more

Solid Principles are a set of five design principles for writing clean, maintainable, and scalable code.

• Single Responsibility Principle: A class should have only one reason to change.

• Open/Closed Principle: Classes should be open for extension but closed for modification.

• Liskov Substitution Principle: Objects of a superclass should be replaceable with objects of its subclasses without affecting the program's correctness.

• Interface Segregation Principle: Clients should not be fo...read more

Web Components are a set of web platform APIs that allow you to create new custom, reusable, encapsulated HTML tags to use in web pages and web apps.

• Web Components consist of four main technologies: Custom Elements, Shadow DOM, HTML Templates, and HTML Imports.

• Custom Elements allow developers to define their own custom HTML elements.

• Shadow DOM provides encapsulation for the custom elements, ensuring that styles and scripts do not affect other parts of the document.

• HTML Templa...read more

Web traffic file is a log file that records all incoming and outgoing traffic on a website.

• Web traffic files typically include information such as IP addresses, timestamps, URLs visited, and HTTP status codes.

• These files are commonly used for analyzing website performance, identifying security threats, and monitoring user activity.

• Examples of web traffic file formats include Apache access logs (access.log) and Nginx access logs (access.log).