AI solution for Interview Question on BFE.dev
5.`var` vs `let` vs `const`

The general rule is to use let when you need to reassign the variable value and use const when you don't.

The technical difference between var, let and const is the scope and reassigning of the variable value. var has a function scope, meaning it can be accessed within the function it was defined in or any nested functions. let and const, on the other hand, have block scope, meaning they can only be accessed within the block they were defined in (a block is anything between curly braces {}).

Additionally, var allows to re-declare and reassign the variable value within its scope, while let allows only re-assignment and const doesn't allow any re-declaration or re-assignment, making it a completely read-only variable. It is important to note that when using const with objects or arrays, you can still modify their properties or elements, but cannot completely reassign them to a new value.

Overall, it is recommended to use let and const over var due to their block scope and stricter rules, promoting cleaner and safer code.