What is 'Branded Types' (Nominal Typing) and why use it for IDs?

Branding simulates nominal typing by adding a unique 'tag' to a type, preventing identical structural types from being swapped.

TS is structural; two strings are the same. This leads to bugs where a 'UserId' (string) is passed to a function expecting an 'AccountId' (string). Branding involves intersecting a type with a unique object property. While the property doesn't exist at runtime, the compiler treats them as distinct types, forcing the developer to perform a 'validated cast' and preventing accidental swaps.