In with let

let is the sensible replacement for var. Anywhere we used var correctly before, we can replace it with let. let removes the issues that plague var and is less error prone.

No redefinition

let does not permit a variable in a scope to be redefined. Unlike var, let behaves a lot like variable definitions in other languages that strictly enforce variable declarations and scope. If a variable is already defined, using let to redefine that variable will result in an error.

Example