How to expose types returned by API in typescript

I am creating a typescript library that can call web services and return data. It provides an API to call the different web services. Each API call returns data of a certain type. In my main module, I export the API.

I can't figure out the best way to expose the types returned by the API. Given that the types have sub-types and so on, there at least 100 types. For readability and abstraction I put them in multiple files.

I thought I could put all the types in the same namespace and then just expose the namespace. I couldn't figure out how to export a single namespace though in typescript. This lead me to believe there is a different way to tackle this problem but I'm not sure what.

Example:

// api.ts
expose function getData(): IData;
expose function getData2(): IData2;

// IData1.ts
export interface IData1 {
    subData: ISubData1;
}

export interface ISubData1: {
    value: string;
}

// IData2.ts
export interface IData2 {
    subData: ISubData2;
}

export interface ISubData2: {
    subSubData: ISubSubData2;
}

export interface ISubSubData2 {
    value: string;
}

// index.ts
import * as api from "./api";
export {api};

// What is the best way to export the type interfaces so that the consumer of this library has type checking?