fix: add @babel/preset-env in rollup config (#336)

Closes #335

Author: gregberge

package.json

@@ -6,11 +6,11 @@
   "bundlesize": [
     {
       "path": "./packages/component/dist/loadable.min.js",
-      "maxSize": "2 kB"
+      "maxSize": "2.5 kB"
     },
     {
       "path": "./packages/component/dist/loadable.esm.js",
-      "maxSize": "3 kB"
+      "maxSize": "3.5 kB"
     }
   ],
   "scripts": {

packages/component/.size-snapshot.json

@@ -1,20 +1,20 @@
 {
   "dist/loadable.cjs.js": {
-    "bundled": 10177,
-    "minified": 5008,
-    "gzipped": 1931
+    "bundled": 12669,
+    "minified": 6097,
+    "gzipped": 2189
   },
   "dist/loadable.esm.js": {
-    "bundled": 9858,
-    "minified": 4743,
-    "gzipped": 1857,
+    "bundled": 12286,
+    "minified": 5788,
+    "gzipped": 2122,
     "treeshaked": {
       "rollup": {
-        "code": 3158,
-        "import_statements": 60
+        "code": 259,
+        "import_statements": 259
       },
       "webpack": {
-        "code": 4211
+        "code": 5063
       }
     }
   }

packages/component/rollup.config.js

@@ -19,7 +19,10 @@ const external = id => !id.startsWith('.') && !id.startsWith('/')
 const getBabelOptions = ({ useESModules }) => ({
   exclude: '**/node_modules/**',
   runtimeHelpers: true,
-  presets: [['@babel/preset-react', { useBuiltIns: true }]],
+  presets: [
+    ['@babel/preset-env', { loose: true }],
+    ['@babel/preset-react', { useBuiltIns: true }],
+  ],
   plugins: [
     '@babel/plugin-proposal-class-properties',
     'babel-plugin-annotate-pure-calls',