Docs update for asyncOptions plus "nicety"

README.md

@@ -13,7 +13,7 @@ Live demo: [jedwatson.github.io/react-select](http://jedwatson.github.io/react-s
 
 To build the examples locally, run:
 
-```
+```javascript
 npm install
 npm start
 ```
@@ -36,7 +36,7 @@ It's loosely based on [Selectize](http://brianreavis.github.io/selectize.js/) (i
 
 The easiest way to use React-Select is to install it from NPM and include it in your own React build process (using [Browserify](http://browserify.org), etc).
 
-```
+```javascript
 npm install react-select --save
 ```
 
@@ -57,7 +57,7 @@ The `value` property of each option should be set to either a string or a number
 
 When the value is changed, `onChange(newValue, [selectedOptions])` will fire.
 
-```
+```javascript
 var Select = require('react-select');
 
 var options = [
@@ -100,7 +100,7 @@ The select control will intelligently cache options for input strings that have
 
 Unless you specify the property `autoload={false}` the control will automatically load the default set of options (i.e. for `input: ''`) when it is mounted.
 
-```
+```javascript
 var Select = require('react-select');
 
 var getOptions = function(input, callback) {
@@ -124,11 +124,46 @@ var getOptions = function(input, callback) {
 />
 ```
 
+### Async options with Promises
+
+`asyncOptions` now supports Promises, which can be used in very much the same way as callbacks.
+
+Everything that applies to `asyncOptions` with callbacks still applies to the Promises approach (e.g. caching, autoload, ...)
+
+An example using the `fetch` API and ES6 syntax, with an API that returns an object like:
+
+```javascript
+import Select from 'react-select';
+
+/*
+ * assuming the API returns something like this:
+ *   const json = [ 
+ * 	   { value: 'one', label: 'One' },
+ * 	   { value: 'two', label: 'Two' }
+ *   ]
+ */
+
+const getOptions = (input) => {
+  return fetch(`/users/${input}.json`)
+    .then((response) => {
+      return response.json();
+    }).then((json) => {
+      return { options: json };
+    });
+}
+
+<Select
+	name="form-field-name"
+	value="one"
+	asyncOptions={getOptions}
+/>
+```
+
 ### Async options loaded externally
 
 If you want to load options asynchronously externally from the `Select` component, you can have the `Select` component show a loading spinner by passing in the `isLoading` prop set to `true`.
 
-```
+```javascript
 var Select = require('react-select');
 
 var isLoadingExternally = true;
@@ -208,7 +243,7 @@ For multi-select inputs, when providing a custom `filterOptions` method, remembe
 
 Right now there's simply a `focus()` method that gives the control focus. All other methods on `<Select>` elements should be considered private and prone to change.
 
-```js
+```javascript
 // focuses the input element
 <instance>.focus();
 ```