Use ES Modules over CommonJS.

MIGRATION.md

@@ -2,6 +2,31 @@
 
 ## Migrating from v3 to v4
 
+v4 changes the default export to the constructor. It also uses [ES Modules over CommonJS](https://hacks.mozilla.org/2018/03/es-modules-a-cartoon-deep-dive/) syntax. We recommend to include `ftdomdelegate` using the es modules syntax.
+
+If you used the `.Delegate` constructure update your import:
+
+```diff
+-const Delegate = require('ftdomdelegate').Delegate;
++import Delegate from 'ftdomdelegate';
+let myDel = new Delegate(document.body);
+```
+
+If you used the previous default export, also update to use the constructor:
+```diff
+-const delegate = require('ftdomdelegate');
+-let myDel = delegate(document.body);
++import Delegate from 'ftdomdelegate';
++let myDel = new Delegate(document.body);
+```
+
+However to use the CommonJS syntax, without a plugin like [babel-plugin-transform-es2015-modules-commonjs](https://babeljs.io/docs/en/babel-plugin-transform-es2015-modules-commonjs), add `.default`.
+
+```diff
+-const Delegate = require('ftdomdelegate').Delegate;
++const Delegate = require('ftdomdelegate').default;
+let myDel = new Delegate(document.body);
+```
 
 ## Migrating from v2 to v3
 

README.md

@@ -36,23 +36,16 @@ The easiest way is to include the following script tag and let [Polyfill.io](htt
 <script src="https://cdn.polyfill.io/v2/polyfill.js?features=Event,Array.prototype.map,Function.prototype.bind,document.querySelector,Element.prototype.matches"></script>
 ```
 
-## Usage ##
+## Usage
 
-The library is written in CommonJS and so can be `require` in.
+To import ftdomdelegate:
 
 ```js
-// If requiring the module via CommonJS, either:-
-Delegate = require('ftdomdelegate').Delegate;
-myDel = new Delegate(document.body);
-
-// Or:-
-delegate = require('ftdomdelegate');
-myDel = delegate(document.body);
+import Delegate from 'ftdomdelegate';
+let myDel = new Delegate(document.body);
 ```
 
-The script must be loaded prior to instantiating a Delegate object.
-
-To instantiate Delegate on the `body` and listen to some events:
+To instantiate `Delegate` on the `body` and listen to some events:
 
 ```js
 function handleButtonClicks(event) {
@@ -70,7 +63,6 @@ document.addEventListener('DOMContentLoaded', function() {
   // Listen to all touch move
   // events that reach the body
   delegate.on('touchmove', handleTouchMove);
-
 });
 ```