var is function-scoped, can be re-declared/reassigned, and is hoisted with undefined .
let is block-scoped, can be reassigned but not re-declared, and prevents scope issues.
const is block-scoped, cannot be reassigned, but objects/arrays can be modified

map():Iterates over an array, applies a transformation,and returns a new modified array.
forEach():Iterates over an array but does not return a new array; mainly used for side effects like logging.
filter():Iterates over an array and returns a new array with elements that satisfy a given condition.

Arrow functions are a shorthand way to write functions in JavaScript, introduced in ES6.
They are different from regular functions in terms of syntax, this binding, and usage.

A Promise in JavaScript represents a value that may be available now, in the future, or never. It is used for handling asynchronous operations
like API calls, file reading, or timers.

A closure is a function that remembers and can access its lexical scope or the scope in which it was defined,
even when the function is executed outside that scope. Closures are a powerful feature of
JavaScript and are often used for data encapsulation, callbacks, and creating function factories