Hoisting, Scope & the TDZ
Before code runs, JavaScript registers every declaration in its scope. var is created as undefined, functions are created fully, and let/const/class exist but can't be touched until their line runs (the temporal dead zone).
Before code runs, JavaScript registers every declaration in its scope. var is created as undefined, functions are created fully, and let/const/class exist but can't be touched until their line runs (the temporal dead zone).