onchange parallelshel concurrently

 npm install -D  onchange   parallelshel  concurrently

 "watch:lint": "onchange -i "**/*.js" "**/*.less" -- npm run lint",
 "watch:test": "npm t -- --watch",
 "watch:all": "parallelshell "npm run watch:scss""npm run lite""

　　"start": "concurrently "react-scripts start" "npm run mock"",