Issue with isolatedModules turn on in project

[iroy2000]

I'm using webpack 4.28.4 and typescript 3.5.1.

I tried to install the comlink-loader, everything seems fine, but it complain my worker is not a module.

All files must be modules when the '--isolatedModules' flag is provided.

// something.worker.ts

import { doSomething } from './util';

export const processSomething = async(payload) => {
  return doSomething(payload);
}

This is my webpack config for comlink-loader, it is basically copy and paste.

  {
    test: /\.worker\.ts$/i,
    use: [{
      loader: 'comlink-loader',
      options: {
        singleton: true
      }
    }]
  },

Do you see if I'm missing anything here ?