note about Map and WeakMap

brigand · Oct 24, 2017 · e8bb27d · e8bb27d
1 parent 4f9d955
commit e8bb27d
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/README.md b/README.md
@@ -12,6 +12,10 @@ It's smart enough to not remove class names added in mutlipe places, and to main
 npm install --save react-global-style
 ```
 
+You may need a polyfill for the ES6 features `Map` and `WeakMap`. These are included in [babel-polyfill], which many apps already use.
+
+[babel-polyfill]: https://babeljs.io/docs/usage/polyfill/
+
 ## Usage
 
 ```jsx