Improve babel config

- enable loose mode for env and class properties
- reuse helpers from babel runtime instead of duplicating them

.babelrc

@@ -1,11 +1,11 @@
 {
   "presets": [
-    ["@babel/env", { "modules": false }],
+    ["@babel/env", { "modules": false, "loose": true }],
     "@babel/flow",
     "@babel/react"
   ],
   "plugins": [
-    "@babel/proposal-class-properties"
+    ["@babel/proposal-class-properties", { "loose": true }]
   ],
   "env": {
     "test": {

.size-snapshot.json

@@ -1,25 +1,25 @@
 {
   "dist/react-motion.js": {
-    "bundled": 83106,
-    "minified": 24575,
-    "gzipped": 7184
+    "bundled": 76899,
+    "minified": 22572,
+    "gzipped": 6605
   },
   "dist/react-motion.min.js": {
-    "bundled": 59713,
-    "minified": 17814,
-    "gzipped": 5188
+    "bundled": 53506,
+    "minified": 15814,
+    "gzipped": 4568
   },
   "dist/react-motion.esm.js": {
-    "bundled": 49359,
-    "minified": 18664,
-    "gzipped": 4427,
+    "bundled": 42991,
+    "minified": 14453,
+    "gzipped": 3551,
     "treeshaked": {
       "rollup": {
-        "code": 14625,
-        "import_statements": 97
+        "code": 12421,
+        "import_statements": 203
       },
       "webpack": {
-        "code": 15824
+        "code": 13744
       }
     }
   }

package.json

@@ -8,14 +8,15 @@
     "react": "^0.14.9 || ^15.3.0 || ^16.0.0"
   },
   "devDependencies": {
-    "@babel/cli": "^7.0.0-beta.56",
-    "@babel/core": "^7.0.0-beta.56",
-    "@babel/plugin-proposal-class-properties": "^7.0.0-beta.56",
-    "@babel/plugin-transform-modules-commonjs": "^7.0.0-beta.56",
-    "@babel/polyfill": "^7.0.0-beta.56",
-    "@babel/preset-env": "^7.0.0-beta.56",
-    "@babel/preset-flow": "^7.0.0-beta.56",
-    "@babel/preset-react": "^7.0.0-beta.56",
+    "@babel/cli": "^7.0.0-rc.1",
+    "@babel/core": "^7.0.0-rc.1",
+    "@babel/plugin-proposal-class-properties": "^7.0.0-rc.1",
+    "@babel/plugin-transform-modules-commonjs": "^7.0.0-rc.1",
+    "@babel/plugin-transform-runtime": "^7.0.0-rc.1",
+    "@babel/polyfill": "^7.0.0-rc.1",
+    "@babel/preset-env": "^7.0.0-rc.1",
+    "@babel/preset-flow": "^7.0.0-rc.1",
+    "@babel/preset-react": "^7.0.0-rc.1",
     "babel-eslint": "^9.0.0-beta.3",
     "babel-loader": "^8.0.0-beta.4",
     "codemirror": "^5.5.0",
@@ -107,6 +108,7 @@
   ],
   "license": "MIT",
   "dependencies": {
+    "@babel/runtime": "7.0.0-rc.1",
     "performance-now": "^2.1.0",
     "prop-types": "^15.5.8",
     "raf": "^3.1.0"

rollup.config.js

@@ -16,13 +16,15 @@ const globals = {
 const external = id =>
   !id.startsWith('\0') && !id.startsWith('.') && !id.startsWith('/');
 
-const getBabelOptions = () => ({
+const getBabelOptions = ({ useESModules }) => ({
   exclude: '**/node_modules/**',
+  runtimeHelpers: true,
+  plugins: [['@babel/transform-runtime', { useESModules }]],
 });
 
-const getCommonjsOptions = () => ({
+const commonjsOptions = {
   include: '**/node_modules/**',
-});
+};
 
 export default [
   {
@@ -31,8 +33,8 @@ export default [
     external: Object.keys(globals),
     plugins: [
       nodeResolve(),
-      babel(getBabelOptions()),
-      commonjs(getCommonjsOptions()),
+      babel(getBabelOptions({ useESModules: true })),
+      commonjs(commonjsOptions),
       replace({ 'process.env.NODE_ENV': JSON.stringify('development') }),
       sizeSnapshot(),
     ],
@@ -44,8 +46,8 @@ export default [
     external: Object.keys(globals),
     plugins: [
       nodeResolve(),
-      babel(getBabelOptions()),
-      commonjs(getCommonjsOptions()),
+      babel(getBabelOptions({ useESModules: true })),
+      commonjs(commonjsOptions),
       replace({ 'process.env.NODE_ENV': JSON.stringify('production') }),
       sizeSnapshot(),
       uglify(),
@@ -56,13 +58,13 @@ export default [
     input,
     output: { file: pkg.module, format: 'esm' },
     external,
-    plugins: [babel(getBabelOptions()), sizeSnapshot()],
+    plugins: [babel(getBabelOptions({ useESModules: true })), sizeSnapshot()],
   },
 
   {
     input,
     output: { file: pkg.main, format: 'cjs' },
     external,
-    plugins: [babel(getBabelOptions())],
+    plugins: [babel(getBabelOptions({ useESModules: false }))],
   },
 ];