npm ERR! extraneous while doing npm ls -g --depth=0

When I list the top level npm packages using npm ls -g --depth=0, I get the following output. This started happening only after installing the package learnyounode.

$ npm ls -g --depth=0
/home/animesh/.npm-global/lib
├── aurelia-cli@0.29.0
├── express@4.15.2
├── gulp@3.9.1
├── jasmine@2.6.0
├── karma@1.7.0
├── learnyounode@3.5.10
├── mocha@3.3.0
├── npm@4.6.1
└── yo@1.8.5

npm ERR! extraneous: csv-stringify@1.0.4 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/csv-stringify
npm ERR! extraneous: eslint@3.14.0 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/eslint
npm ERR! extraneous: eslint-config-standard@6.2.1 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/eslint-config-standard
npm ERR! extraneous: eslint-plugin-promise@3.4.0 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/eslint-plugin-promise
npm ERR! extraneous: eslint-plugin-standard@2.0.1 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/eslint-plugin-standard
npm ERR! extraneous: if-env@1.0.0 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/if-env
npm ERR! extraneous: mockery@2.0.0 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/mockery
npm ERR! extraneous: mustache@2.3.0 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/mustache
npm ERR! extraneous: sprintf@0.1.5 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/sprintf
npm ERR! extraneous: tap@9.0.3 /home/animesh/.npm-global/lib/node_modules/learnyounode/node_modules/i18n-core/node_modules/tap

My npm prefix, node and npm versions

/home/animesh/.npm-global
v6.10.3
4.6.1

Any suggestions on how I might fix this?

via Animesh