Empty functions or interfaces?

[AbdelrhmanAmin]

I have noticed a re-occurring pattern in Redux that I don't understand.
What are those empty functions before the actual function? The actual function starts after the red line I drew on the screenshot.

applyMiddleware.ts

compose.ts

Thanks.

[markerikson]

That's TypeScript "method overloading". It tells TS that there are multiple valid ways to call those functions, with varying arguments and signatures, even though there's only one JS implementation:

• https://www.typescriptlang.org/docs/handbook/2/functions.html#function-overloads
• https://dmitripavlutin.com/typescript-function-overloading/

[AbdelrhmanAmin]

Thank you :)