Immutable by default can still be a strict superset of JS. It just requires treating const assignments and function parameters as Readonly (or ReadonlyArray/Rea

Immutable by default can still be a strict superset of JS. It just requires treating const assignments and function parameters as Readonly (or ReadonlyArray/ReadonlyMap/ReadonlySet) and introducing a Mutable type/mutable keyword. In my own personal projects I make nearly everything immutable at the type level and, while it makes my code safer it’s an enormous pain in the butt to type readonly on every property. As a matter of habit it has one other benefit though: you never have to worry about accepting `as const` values in function calls.