var js

1// `let` vs `var` vs `const` in 'javascript'
2
3"let" allows you to declare local variable whose scope 
4      is limited to the block statement.
5
6"var" allows you to declare a variable globally or locally 
7      to an entire function.
8
9"Const" just like let, are block-scoped.
10        It's value can't be reassigned and it can't be redeclared.
11

1var num = 1: