`my-enum.ts`: ```ts export const enum Test { value1 = 'value1', value2 = 'value2' } ``` `my-enum.js`: ```js "use strict"; Object.defineProperty(exports, "__esModule", { value: true }); exports.Test = void 0; var Test; (function (Test) { Test["value1"] = "value1"; Test["value2"] = "value2"; })(Test = exports.Test || (exports.Test = {})); //# sourceMappingURL=my-enum.js.map ``` `my-extend.ts`: ```ts import { Test } from './my-enum'; declare module './my-enum' { export const enum Test { value3 = 'value3' } } console.log(Test.value3); ``` `my-extend.js`: ```js "use strict"; Object.defineProperty(exports, "__esModule", { value: true }); require("./my-enum"); console.log("value3" /* value3 */); //# sourceMappingURL=my-extend.js.map ```