 So what happens if something gets removed from our package JSON but leaves on in our node modules? Let's edit our package JSON and remove React DOM. Now we removed it from the package JSON but it leaves on in node modules. Let's see what happens if we run npmls. We get a great error saying that we have an extraneous dependency. So what do we do with extraneous dependencies? Also glad you asked. There's a great npm command for that called npm prune. npm prune just does the work of removing dependencies from the node modules directory that are no longer represented in the package JSON file. Run npmls again. Everything should come up aces.