Line 2: 'react-sortable-hoc' should be listed in the project's dependencies. Run 'npm i -S react-sortable-hoc' to add it import/no-extraneous-dependencies

  Line 2:  'react-sortable-hoc' should be listed in the project's dependencies. Run 'npm i -S react-sortable-hoc' to add it  import/no-extraneous-dependencies

package.json 파일에 

"react-sortable-hoc": "^0.8.3",

이런 식으로 추가하면 됨.