npm shrinkwrap add devDependencies by default

log

$ vim package.json
$ npm i
tmp@1.0.0 /home/philip/workspace/aggie_ws/tmp
├── ms@0.7.2 
└── wrappy@1.0.2 

npm WARN tmp@1.0.0 No description
npm WARN tmp@1.0.0 No repository field.
$ npm shrinkwrap
wrote npm-shrinkwrap.json

npm-shrinkwrap.json

{
  "name": "tmp",
  "version": "1.0.0",
  "dependencies": {
    "ms": {
      "version": "0.7.2",
      "from": "ms@>=0.7.2 <0.8.0",
      "resolved": "https://registry.npmjs.org/ms/-/ms-0.7.2.tgz"
    },
    "wrappy": {
      "version": "1.0.2",
      "from": "wrappy@>=1.0.2 <2.0.0",
      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
      "dev": true
    }
  }
}

package.json

{
  "name": "tmp",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "wrappy": "^1.0.2"
  },
  "dependencies": {
    "ms": "^0.7.2"
  }
}