Why do you have to export something in a declaration file to define things in the global scope?

[adriancuadrado]

Page URL: https://www.typescriptlang.org/docs/handbook/declaration-files/templates/global-modifying-module-d-ts.html

Issue: The example given has a comment that says this:

If your module exports nothing, you'll need this line. Otherwise, delete it

However, it doesn't explain why. If it is explained anywhere, it would be nice to include a link to it.

[jakebailey]

For backwards compatibility; declaration files without exports are assumed to augment the global scope, not contain only locals.