In Harmony, there is a let keyword that allows for declaration of variables that are scoped to the nearest block. For example
function foo() {
    if (true){
        let a = 100;
    }
    return a
}
will result in an error since a is only defined inside the if block.
I know I can use del to achieve the same thing, but that that is manual instead of automatic like the let keyword
 
    