TypeScript has the equivalent of what you're describing via the `Parameters` and `ReturnType` utility types [1][2], and I've found these types indispensable. So

TypeScript has the equivalent of what you're describing via the `Parameters` and `ReturnType` utility types [1][2], and I've found these types indispensable. So you can do the following: type R = ReturnType<typeof someFunction> type P = Parameters<typeof someFunction> [1] https://www.typescriptlang.org/docs/handbook/utility-types.html#parameterstype https://www.typescriptlang.org/docs/handbook/utility-types.h... [2] https://www.typescriptlang.org/docs/handbook/utility-types.html#returntypetype https://www.typescriptlang.org/docs/handbook/utility-types.h...