feat(es2015): add es2015 implementation to support rollup (#10)

* feat(es2015): add es2015 implementation to support rollup

The build now comes from the es2015 files under the `es/` directory.

closes #9

* chore(package): add es files and lib files to npm files

* chore(package): ensure build and test before publish

* refactor(ponyfill): make Symbol const

* chore(ponyfill test): update tests to look at built file

* refactor(all): ensure only es6 feature used is modules

.babelrc

@@ -0,0 +1,4 @@
+{
+  "presets": ["es2015"],
+  "plugins": ["add-module-exports"],
+}

.gitignore

@@ -1 +1,2 @@
 node_modules
+lib

es/index.js

@@ -0,0 +1,11 @@
+/* global window */
+import ponyfill from './ponyfill';
+
+let root = this;
+if (typeof global !== 'undefined') {
+	root = global;
+} else if (typeof window !== 'undefined') {
+	root = window;
+}
+
+export default ponyfill(root);

ponyfill.js → es/ponyfill.js

@@ -1,6 +1,4 @@
-'use strict';
-
-module.exports = function symbolObservablePonyfill(root) {
+export default function symbolObservablePonyfill(root) {
 	var result;
 	var Symbol = root.Symbol;
 

index.js

@@ -1,10 +1 @@
-/* global window */
-'use strict';
-
-var root = this;
-if (typeof global !== 'undefined') {
-	root = global;
-} else if (typeof window !== 'undefined') {
-	root = window;
-}
-module.exports = require('./ponyfill')(root);
+module.exports = require('./lib/');

package.json

@@ -12,12 +12,18 @@
     "node": ">=0.10.0"
   },
   "scripts": {
-    "test": "mocha"
+    "build": "babel es --out-dir lib",
+    "test": "npm run build && mocha",
+    "prepublish": "npm test"
   },
   "files": [
     "index.js",
     "ponyfill.js",
-    "index.d.ts"
+    "index.d.ts",
+    "es/index.js",
+    "es/ponyfill/js",
+    "lib/index.js",
+    "lib/ponyfill.js"
   ],
   "keywords": [
     "symbol",
@@ -28,6 +34,9 @@
     "shim"
   ],
   "devDependencies": {
+    "babel-cli": "^6.9.0",
+    "babel-plugin-add-module-exports": "^0.2.1",
+    "babel-preset-es2015": "^6.9.0",
     "chai": "^3.5.0",
     "mocha": "^2.4.5"
   }

test/ponyfill.js

@@ -1,6 +1,6 @@
 /* global describe, it */
 var expect = require('chai').expect;
-var ponyfill = require('../ponyfill');
+var ponyfill = require('../lib/ponyfill');
 
 describe('ponyfill unit tests', function () {
   describe('when Symbol does NOT exist as a function', function () {