Note: You cannot change the visibility of an unscoped package. Only scoped packages with a paid subscription may be private.
Making a public package private
Note: Making a package private requires a paid user account or organization. To sign up for a paid user or organization, go to https://www.npmjs.com/settings/account-name/billing, replacing account-name with the name of your npm user account or organization.
If you want to restrict access and visibility for a public package you own, you can make the package private. When you make a package private, its access will be updated immediately and it will be removed from the website within a few minutes of the change.