feat(Storybook): add polyfill and babel-polyfill to support IE/Edge

Author: Rendez

README.md

@@ -171,9 +171,11 @@ Single React component or element that is used as the target (observable).
 
 ### Notes
 
-* According to the spec, a first callback invocation occurs when the target is first attached to the observer.
+* According to the spec, an initial event is being fired when starting to observe a non-intersecting element as well.
+  * _Edge's implementation seems to [miss the initial event](https://github.com/w3c/IntersectionObserver/issues/222#issuecomment-311539591), although Edge 16 behavior aligns with the spec._
 * Changes happen asynchronously, similar to the way `requestIdleCallback` works.
 * Although you can consider callbacks immediate - always below 1 second - you can also get an immediate response on an element's visibility with `observer.takeRecords()`.
+* Support for _Map_, _Symbol_ and other native features and primitives is required. Consider using a polyfill for IE < 11 and older browsers. If you're using babel include `"babel-polyfill"` somewhere to your codebase.
 
 ## Polyfill
 

docs/docs/index.js

@@ -1,3 +1,5 @@
+import 'babel-polyfill';
+import 'intersection-observer';
 import { storiesOf } from '@storybook/react';
 import WindowRoot from './components/WindowRoot';
 import WindowFrame from './components/WindowFrame';

package.json

@@ -19,6 +19,7 @@
     "babel-cli": "^6.24.1",
     "babel-eslint": "^8.0.0",
     "babel-jest": "^21.0.0",
+    "babel-polyfill": "^6.26.0",
     "conventional-github-releaser": "^1.1.12",
     "cross-env": "^5.0.5",
     "css-loader": "^0.28.4",

yarn.lock

@@ -5840,9 +5840,9 @@ range-parser@^1.0.3, range-parser@~1.2.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/range-parser/-/range-parser-1.2.0.tgz#f49be6b487894ddc40dcc94a322f611092e00d5e"
 
-raw-loader@^0.5.1:
-  version "0.5.1"
-  resolved "https://registry.yarnpkg.com/raw-loader/-/raw-loader-0.5.1.tgz#0c3d0beaed8a01c966d9787bf778281252a979aa"
+raw-loader@^1.0.0-beta.0:
+  version "1.0.0-beta.0"
+  resolved "https://registry.yarnpkg.com/raw-loader/-/raw-loader-1.0.0-beta.0.tgz#617853ce8314d1166c06758d9302d24faf08d44c"
 
 rc@^1.1.7:
   version "1.2.1"
@@ -6751,9 +6751,9 @@ style-loader@^0.17.0:
   dependencies:
     loader-utils "^1.0.2"
 
-style-loader@^0.18.2:
-  version "0.18.2"
-  resolved "https://registry.yarnpkg.com/style-loader/-/style-loader-0.18.2.tgz#cc31459afbcd6d80b7220ee54b291a9fd66ff5eb"
+style-loader@^0.19.0:
+  version "0.19.0"
+  resolved "https://registry.yarnpkg.com/style-loader/-/style-loader-0.19.0.tgz#7258e788f0fee6a42d710eaf7d6c2412a4c50759"
   dependencies:
     loader-utils "^1.0.2"
     schema-utils "^0.3.0"