JavaScript Developer interview questions

JavaScript is a versatile language known for its dynamic typing, event-driven programming, prototype-based inheritance, and first-class functions.

Var' declares a variable globally or within the function scope, 'let' declares a block-scoped variable, and 'const' declares a block-scoped constant whose value cannot be reassigned.

Closures in JavaScript allow a function to access variables from an outer function scope even after the outer function has finished executing.

The 'this' keyword in JavaScript refers to the object it belongs to, and its value is determined based on the execution context in which a function is invoked.

Event delegation is a technique in JavaScript where a single event listener is added to a parent element to manage events from multiple child elements through event bubbling.

Promises in JavaScript are objects representing the eventual completion or failure of an asynchronous operation, allowing for easier handling of asynchronous code.

Arrow functions are a more concise way to write function expressions with a lexical 'this' binding, meaning they do not have their own 'this' value and inherit 'this' from the enclosing scope.

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during execution.

Synchronous code is executed line by line in sequence, whereas asynchronous code allows executing tasks to run in the background without blocking the main thread.

Errors in JavaScript can be handled using 'try', 'catch', 'finally' blocks to catch exceptions, or by employing Promises and 'async/await' mechanisms for handling asynchronous operations.