package.json fails with cb() never called

package.json

{
  "name": "x2",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.16.4",
    "react": "^16.5.2",
    "react-dom": "^16.5.2",
    "redux": "^4.0.1",
    "xclap": "^0.2.24"
  },
  "devDependencies": {
    "babel-cli": "^6.4.5",
    "babel-core": "^6.4.0",
    "babel-eslint": "^8.1.2",
    "babel-jest": "^23.4.2",
    "babel-loader": "^7.0.0",
    "babel-plugin-dynamic-import-node": "^1.2.0",
    "babel-plugin-i18n-id-hashing": "^2.1.0",
    "babel-plugin-lodash": "^3.1.3",
    "babel-plugin-minify-dead-code-elimination": "^0.1.7",
    "babel-plugin-react-css-modules": "^3.4.2",
    "babel-plugin-react-intl": "^2.1.2",
    "babel-plugin-transform-node-env-inline": "^0.1.1",
    "babel-plugin-transform-object-rest-spread": "^6.3.13",
    "babel-plugin-transform-react-constant-elements": "^6.5.0",
    "babel-plugin-transform-react-inline-elements": "^6.6.5",
    "babel-plugin-transform-react-remove-prop-types": "^0.4.8",
    "babel-plugin-transform-runtime": "^6.8.0",
    "babel-polyfill": "^6.5.0",
    "babel-preset-env": "^1.6.1",
    "babel-preset-react": "^6.3.13",
    "chai": "^4.0.0",
    "chai-as-promised": "^7.1.1",
    "chai-shallowly": "^1.0.0",
    "clean-css": "^3.4.21",
    "convert-source-map": "^1.5.0",
    "css-loader": "^0.28.9",
    "css-split-webpack-plugin": "^0.2.0",
    "enzyme": "^3.0.0",
    "enzyme-adapter-react-16": "^1.1.0",
    "eslint": "^4.8.0",
    "extract-text-webpack-plugin": "^3.0.0",
    "file-loader": "^0.11.1",
    "finalhandler": "^1.1.1",
    "identity-obj-proxy": "^3.0.0",
    "json-loader": "^0.5.7",
    "jsonfile": "^2.2.2",
    "mime": "^1.0.0",
    "mkdirp": "^0.5.1",
    "mocha": "^4.0.0",
    "nodemon": "^1.8.1",
    "offline-plugin": "^4.6.1",
    "opn": "^5.3.0",
    "prop-types": "^15.5.6",
    "raw-loader": "^0.5.1",
    "require-at": "^1.0.0",
    "rimraf": "^2.4.0",
    "sinon": "^4.0.0",
    "sinon-chai": "^2.14.0",
    "style-loader": "^0.20.1",
    "stylus": "^0.54.5",
    "stylus-relative-loader": "^3.4.0",
    "uglify-js": "^3.0.26",
    "url-loader": "^0.6.2"
  }
}