Babel Interop Defaults might lead to confusion with ES6 Modules and imports/exports

export.js

//define module-a.js
export default { x: 8 }

//then in module-b.js
import {x} from './module-a';
console.log(x); 
// ^^^ outputs 8 with default Babel settings while according to ES6 spec should output "undefined"
//this is explained by the following quote: 
 
 /* In order to encourage the use of CommonJS and ES6 modules, when exporting a default export with no other exports
    module.exports will be set in addition to exports["default"].
    Source: http://babeljs.io/docs/usage/modules/ (see Interop section)
 */
 
 //to achieve the same with vanilla ES6 modules you would have to do
 export const x = 8;
 export default { x }; // not required, but if you want defaults to be supported you would have to export twice
 
 //this might not be obvious and lead to some WTF's when you will be switching to strict mode after Interop freindly.