[bikitan]

But why would any of that need to be done manually in a .d.ts file? You can just write your type definitions in ts files

[austin-cheney]

Types are meta data for the compiler. They are not code that is compiled to JavaScript, so I isolate my type definitions to d.ts files. That is the only reason I have d.ts files at all.

[sharlos201068]

Types are also documentation for the developers reading and editing the code.