Deep dive into core JavaScript concepts. Some questions related to algorithms. Example: What is JavaScript? JavaScript is a high-level, interpreted programming language primarily used for building interactive and dynamic web applications. What are the different data types in JavaScript? JavaScript has several data types, including numbers, strings, booleans, objects, arrays, functions, and symbols (ES6). What is the difference between null and undefined? null is an intentional absence of any value, while undefined signifies an uninitialized or missing value. Explain hoisting in JavaScript. Hoisting is a behavior in which variable and function declarations are moved to the top of their containing scope during compilation. What is closure in JavaScript? A closure is a function that retains access to its enclosing scope's variables even after the parent function has finished executing. What is the 'this' keyword in JavaScript? this refers to the context in which a function is executed. Its value depends on how a function is invoked. What is the purpose of the 'bind' method? The bind method is used to create a new function with a specific this context, ensuring that the function will always be called with that context. How does event delegation work? Event delegation is a technique where a single event handler is attached to a higher-level element, allowing it to listen for events from its child elements. This is used to optimize performance and handle dynamically added elements. Explain the concept of callbacks. Callbacks are functions that are passed as arguments to other functions and are executed after a certain operation completes. They are often used in asynchronous programming, like handling AJAX requests or timers. What are promises in JavaScript? Promises are a way to handle asynchronous operations in a more structured manner. They represent a value that might be available now, or in the future, or never.