Generate nix expressions from npmjs.org!
npm2nix [--no-dev] node-packages.json node-packages.generated.nix
no-dev ignores development dependencies
npm2nix expects the passed JSON file to be a list of strings and at most one
object. Strings are taken as the name of the package. The object must be
a valid dependencies object for an for an npm
Alternatively, the passed JSON file can be an npm
package.json, in which
case the expressions for its dependencies will be generated.