Exporting classes and interfaces in a module in typescript for node.js package

I have one interface for Exception and one concrete class which inherited from that interface. I wish to export these types in a module as a node.js package.

iexp.ts

interface IException {}

exp.ts

class Exception implements IException {}

index.ts

module AB_Company {
    export IException;
    export Exception;
}
export {AB_Company};

The codes below just for seeing the scene. But I couldn't achieve to export this module.

the client will be used like this

import {AB_Company} from "AB_Company_Exception";
let exp:AB_Company.IException;

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