Can you elaborate on this? const and let should be interchangeable from a performance perspective because it's not like the engine needs your input to know whet

Can you elaborate on this? const and let should be interchangeable from a performance perspective because it's not like the engine needs your input to know whether a binding is reassigned ever (that's a fundamentally easy thing for a compiler to check) so I must conclude that you're seeing performance benefits from using block scoped variables with TDZ that disappear when you use function scoped variables with var?