allow multiple + different tag types

Author: antony

README.MD

@@ -6,7 +6,7 @@
 
 [![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg)](http://standardjs.com) [![CircleCI](https://circleci.com/gh/beyonk-adventures/async-script-loader.svg?style=shield)](https://circleci.com/gh/beyonk-adventures/async-script-loader)
 
-Allows asynchronous loading of scripts in a Single Page Application (or anything else, in fact):
+Allows asynchronous loading of scripts and styles in a Single Page Application (or anything else, in fact):
 
 * Using a test to ensure that the code is only loaded once
 * Running a callback once the script is loaded
@@ -19,6 +19,12 @@ Having integrated a multitude of third-party SDKs from large, well known provide
 
 ### Usage
 
+You pass a list of urls to the loader, along with a method for checking that your page is ready, and a callback to call when it is.
+
+Urls can be scripts or stylesheets.
+
+### Script Tags
+
 You can use the module like so, for a library loaded from example.com, which, when loaded, adds an attribute called PROVIDER to the global window object.
 
 ```js
@@ -35,7 +41,31 @@ You can use the module like so, for a library loaded from example.com, which, wh
     window.PROVIDER.someFunction()
   }
 
-  loader(url, test, callback, { async: true, defer: true })
+  loader([
+    { type: 'script', url }
+  ], test, callback)
+</script>
+```
+
+#### Style Tags
+
+You can include any number of tags, including style tags.
+
+When the last one has loaded, the callback will be called.
+
+```js
+<script>
+  import loader from '@beyonk/async-script-loader'
+
+  loader([
+    { type: 'script', url: '//example.com/sdk/1.0.0/lib.js' },
+    { type: 'script', url: '//example.com/sdk/1.0.0/lib2.js' },
+    { type: 'style', url: '//example.com/sdk/1.0.0/style.css' }
+  ], () => {
+    return !!window.PROVIDER
+  }, () => {
+    window.PROVIDER.someFunction()
+  })
 </script>
 ```
 

index.js

@@ -1,11 +1,28 @@
-export default function (url, test, callback, options = { async: true, defer: true }) {
+export default function (urls, test, callback) {
+  let remaining = urls.length
+
+  function maybeCallback () {
+    remaining = --remaining
+    if (remaining < 1) {
+      callback()
+    }
+  }
+
   if (!test()) {
-    const tag = document.createElement('script')
-    tag.src = url
-    tag.async = options.async
-    tag.defer = options.defer
-    tag.onload = callback
-    document.body.appendChild(tag)
+    urls.forEach(({ type, url, options = { async: true, defer: true }}) => {
+      const isScript = type === 'script'
+      const tag = document.createElement(isScript ? 'script': 'link')
+      if (isScript) {
+        tag.src = url
+        tag.async = options.async
+        tag.defer = options.defer
+      } else {
+        tag.rel = 'stylesheet'
+		    tag.href = url
+      }
+      tag.onload = maybeCallback
+      document.body.appendChild(tag)
+    })
   } else {
     callback()
   }