npx installs "undefined" npm package

[JoshWhite]

Running install-peerdeps (at least via npx on Windows) causes https://www.npmjs.com/package/undefined to be installed as a dependency.

Repro steps

npm init
npx install-peerdeps --dev eslint-config-airbnb

Output:

C:\experiments\install-peerdeps-bug>npx install-peerdeps --dev eslint-config-airbnb
npx: installed 82 in 27.915s
install-peerdeps v1.10.1
Installing peerdeps for eslint-config-airbnb@latest.
npm install eslint-config-airbnb@17.1.0 eslint@5.3.0 eslint-plugin-import@^2.14.0 eslint-plugin-jsx-a11y@^6.1.1 eslint-plugin-react@^7.11.0 --save-dev

npm WARN deprecated undefined@0.1.0: this package has been deprecated
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN install-peerdeps-bug@1.0.0 No description
npm WARN install-peerdeps-bug@1.0.0 No repository field.

+ eslint-config-airbnb@17.1.0
+ undefined@0.1.0
+ eslint-plugin-import@2.14.0
+ eslint-plugin-react@7.11.0
+ eslint-plugin-jsx-a11y@6.1.1
+ eslint@5.3.0
added 194 packages from 106 contributors in 62.956s
SUCCESS eslint-config-airbnb
  and its peerDeps were installed successfully.

C:\experiments\install-peerdeps-bug>

Environment

Windows 10
npm v6.4.1
node v10.13.0

Further info

It doesn't do this, when you add the --extraArgs flag.

[nathanhleung]

Thanks for catching this! Will fix ASAP

[nathanhleung]

Also, I think you're right on with why this is happening, so kudos!