🔥 Don't transpile files under __tests__

Author: cooperka

package.json

@@ -11,7 +11,7 @@
     "test": "jest",
     "lint": "eslint src example/src --ext .js,.jsx",
     "clean": "rm -rf lib",
-    "build": "npm run clean && babel src --out-dir lib",
+    "build": "npm run clean && babel src --out-dir lib --ignore src/__tests__",
     "prepublish": "npm run build"
   },
   "jest": {