exporting enum from typescript type definition file

Solved it by the help of Romain Denau’s comment above. It nudged me in the right direction: What code does the typescript compiler generate from an enum (see https://www.typescriptlang.org/docs/handbook/enums.html#enums-at-runtime)? Declaring the enum const allows the typescript compiler to completely swap the identifier with the respective value, effectively inlining it. No more leakage of the enum into the production code. Thanks!

//index.d.ts
export as namespace myLib;

export const enum MouseButton {
    LEFT = 1,
    MIDDLE = 2,
    RIGHT = 4
}

export function activate(button : MouseButton ) : void;