The DTS file https://github.com/drudru/ansi_up/blob/master/ansi_up.d.ts used in `package.json` does not have default export. The proper file which should be referenced in `types` property of `package.json` is https://github.com/drudru/ansi_up/blob/master/dist/ansi_up.d.ts (it has the default export).