title: How can I prevent the React build and npm from adding files to the project?
body: <p>I have Visual Studio 2019 Professional and we use Azure DevOps TFS for our source control. I am working on a brand new Asp.Net Core 5  app with React. There are two developers on this project including me. Somehow <code>./ClientApp/node_modules/</code> and <code>./ClientApp/build/</code> got placed in TFS. When I check in I have to exclude these two directories every time...</p>
  <p>I have tried adding these two directories to a <code>.tfignore</code> in <code>ClientApp</code> but it seems these are ignored now. I have also marked both Hidden.</p>
  <p>How can I prune these directories from TFS and prevent the build and npm from adding files back to the project?</p>