The command is simply
npm uninstall <name>
The Node.js documents https://npmjs.org/doc/ have all the commands that you need to know with npm.
A local install will be in the
node_modules/ directory of your application. This won't affect the application if a module remains there with no references to it.
If you're removing a global package, however, any applications referencing it will crash.
Here are different options:
npm uninstall <name> removes the module from
node_modules but does not update
npm uninstall <name> --save also removes it from
npm uninstall <name> --save-dev also removes it from
npm uninstall -g <name> --save also removes it globally