Externalize babel helpers using @babel/runtime (#60)

* Externalize babel helpers using @babel/runtime

* [package-lock.json] restore dev flags

Author: petermikitsh

.babelrc

@@ -21,6 +21,7 @@
   },
   "plugins": [
     "@babel/plugin-transform-flow-strip-types",
+    "@babel/plugin-transform-runtime",
     "@babel/plugin-syntax-dynamic-import",
     "@babel/plugin-syntax-import-meta",
     "@babel/plugin-proposal-class-properties",

package-lock.json

@@ -36,7 +36,9 @@
     "@babel/plugin-syntax-dynamic-import": "^7.0.0",
     "@babel/plugin-syntax-import-meta": "^7.0.0",
     "@babel/plugin-transform-flow-strip-types": "^7.0.0",
+    "@babel/plugin-transform-runtime": "^7.2.0",
     "@babel/preset-env": "^7.0.0",
+    "@babel/preset-flow": "^7.0.0",
     "@babel/preset-react": "^7.0.0",
     "@types/react": "^16.4.16",
     "babel-core": "^7.0.0-bridge.0",
@@ -75,8 +77,7 @@
     "rollup-plugin-node-resolve": "^3.4.0",
     "rollup-plugin-replace": "^2.1.0",
     "rollup-plugin-uglify": "^6.0.0",
-    "typescript": "^3.1.3",
-    "@babel/preset-flow": "^7.0.0"
+    "typescript": "^3.1.3"
   },
   "peerDependencies": {
     "final-form": ">=4.0.0",
@@ -112,6 +113,7 @@
     }
   ],
   "dependencies": {
+    "@babel/runtime": "^7.2.0",
     "react-lifecycles-compat": "^3.0.4"
   }
 }

package.json

@@ -49,13 +49,20 @@ export default {
     },
     output
   ),
-  external: [
-    'react',
-    'prop-types',
-    'final-form',
-    'react-final-form',
-    'react-lifecycles-compat'
-  ],
+  external: id => {
+    const externals = [
+      'react',
+      'prop-types',
+      'final-form',
+      'react-final-form',
+      'react-lifecycles-compat'
+    ]
+
+    const isBabelRuntime = id.startsWith('@babel/runtime')
+    const isStaticExternal = externals.indexOf(id) > -1
+
+    return isBabelRuntime || isStaticExternal
+  },
   plugins: [
     resolve({ jsnext: true, main: true }),
     flow(),
@@ -76,6 +83,7 @@ export default {
       ],
       plugins: [
         '@babel/plugin-transform-flow-strip-types',
+        '@babel/plugin-transform-runtime',
         '@babel/plugin-syntax-dynamic-import',
         '@babel/plugin-syntax-import-meta',
         '@babel/plugin-proposal-class-properties',
@@ -90,7 +98,8 @@ export default {
         '@babel/plugin-proposal-export-namespace-from',
         '@babel/plugin-proposal-numeric-separator',
         '@babel/plugin-proposal-throw-expressions'
-      ]
+      ],
+      runtimeHelpers: true
     }),
     umd
       ? replace({