Error bundling bpmn-js: <Unexpected token export>

These are my dev dependencies

"devDependencies": {
    "babel-core": "^6.2.1",
    "babel-loader": "^6.2.0",
    "babel-preset-es2015": "^6.1.18",
    "babel-preset-react": "^6.1.18",
    "webpack": "^1.12.9",
    "webpack-dev-server": "^1.14.0"
  },