JS simply means Javascript by the way

var, let, and const are all keywords used for declaring variables in JavaScript, but they differ in terms of scope, reassignment, and immutability.

var are function-scoped or globally-scoped, which means they are accessible within the function they are declared in, or globally if declared outside a function.

let allows for block-scoped variable declaration. Variables declared with let are limited in scope to the block, statement, or expression in which they are used. let also allows reassignment but not redeclaration within the same scope.

const is used to declare variables that are block-scoped like let, but their values cannot be reassigned once they are initialized. However, it's important to note that while the value itself cannot be reassigned, for objects and arrays declared with const, their internal properties or elements can still be changed.

I will drop examples in the next post, drop questions or comments
Thanks