Typescript module syntax

Question

In typescript, what is the difference between these two:

declare module foo { ... }

and

declare namespace foo { ... }

From the docs I get the feeling they should be the same and the second one is preferred. However I see many .d.ts files that uses the first one which makes me unsure.

Answer 1

They are exactly the same. The keyword module was deprecated in favor of namespace in this case.

More

This is because module confuses the with the concept of file modules : https://basarat.gitbooks.io/typescript/content/docs/project/modules.html