Use @babel/cli to build the library

.babelrc

@@ -2,7 +2,9 @@
   "presets": [
     "@babel/preset-env",
     "@babel/preset-react",
+    {
+      "plugins": ["@babel/plugin-proposal-class-properties"]
+    },
     "@emotion/babel-preset-css-prop"
-  ],
-  "plugins": ["@babel/plugin-proposal-class-properties"]
+  ]
 }

.storybook/.babelrc

@@ -0,0 +1,10 @@
+{
+  "presets": [
+    "@babel/preset-env",
+    "@babel/preset-react",
+    {
+      "plugins": ["@babel/plugin-proposal-class-properties"]
+    },
+    "@emotion/babel-preset-css-prop"
+  ]
+}

package.json

@@ -4,9 +4,13 @@
   "license": "MIT",
   "author": "David Tang",
   "private": false,
-  "main": "dist/bundle.js",
+  "main": "lib/index.js",
   "sideEffects": false,
-  "browserslist": "> 0.25%, not dead",
+  "browserslist": [
+    "maintained node versions",
+    "> 0.25%",
+    "not dead"
+  ],
   "keywords": [
     "react",
     "loading",
@@ -18,12 +22,11 @@
     "type": "git",
     "url": "https://github.com/dvtng/react-loading-skeleton.git"
   },
-  "typings": "./dist/index.d.ts",
   "scripts": {
     "start": "yarn run storybook",
     "test": "jest",
-    "build": "webpack",
-    "storybook": "start-storybook -p 8080 -c .storybook",
+    "build": "babel src --out-dir lib --delete-dir-on-start --copy-files",
+    "storybook": "start-storybook -p 8080",
     "prepublishOnly": "yarn run build"
   },
   "jest": {
@@ -38,6 +41,7 @@
     "react": "^15.6.1 || ^16.0.0"
   },
   "devDependencies": {
+    "@babel/cli": "^7.6.2",
     "@babel/core": "^7.6.2",
     "@babel/plugin-proposal-class-properties": "^7.5.5",
     "@babel/preset-env": "^7.6.2",