In a CommonJS module loaded via Node's ESM interop, `import pkg from "some-cjs-pkg"` gives `pkg` as the module's `module.exports`. Given `esModuleInterop: true`, how does TypeScript's emitted `__importDefault` helper decide what the default binding becomes?
// some-cjs-pkg's module.exports = function () {}
import fn from "some-cjs-pkg";
fn();