ecmascript 6 - What is the use case for var in ES6?

Question

If the let keyword introduces a proper implementation of block scope, does var any longer have a use case? I am looking at this from a software design standpoint rather than a syntactical, "well you could" standpoint.

Answer 1

If the let keyword introduces a proper implementation of block scope, does var any longer have a use case?

There could be one use case: let declarations in global scope don't create a property on the global object. Example:

"use strict"; // for chrome
var foo = 42;
let bar = 21;
console.log('window.foo (var)', window.foo); // 42
console.log('window.bar (let)', window.bar); // undefined