@ -11,6 +11,7 @@ React 16 depends on the collection types [Map](https://developer.mozilla.org/en-
A polyfilled environment for React 16 using core-js to support older browsers might look like:
```js
import 'core-js/es6/promise';
import 'core-js/es6/map';
import 'core-js/es6/set';