bundling typeScript with duplicated import

I am using LigerShark.WebOptimizer.Core package to minimize and bundle css and js files. I have two TypeScript files that import a common utility class. Each file has the declaration like below. At runtime the bundle has the Utility import Utility twice and causes runtime error. How can I resolve the duplicated import? Thanks.

import {Utility} from "./utility.js";

$(function() {
  .....
})

import { ICommonUtility } from "../appModels/ICommonUtility.js";

export class Utility implements ICommonUtility {
......
}

Identifier 'Utility' has already been declared