IT
Так может preset-typescript юзает конфиг тайпскрипта
не 🙂 babel на tsconfig вообще не смотрит, если ты об этом
https://babeljs.io/docs/en/babel-plugin-transform-typescript#caveats 4 пункт
Changes to your tsconfig.json are not reflected in babel. The build process will always behave as though isolatedModules is turned on, there are Babel-native alternative ways to set a lot of the tsconfig.json options however.
