Running ng build on my Angular 4 project give this error :
14% building modules 40/46 modules 6 active ...es\\@angular\\http\\@angular\\htt
So i was having this issue and it took me forever to figure out. I kept trying to delete my node_modules directory then reinstall webpack. If i installed webpack locally or globally i would get the ContextElementDependency error. If i uninstalled webpack i would get webpack not found. Long story short the problem for me was my package-lock.json file. So i ran "rm package-lock.json && rm -R node_modules" and then i could successfully run "npm install" and "npm start". Dont ask me why this works, but i hope this helps someone.