anchor.diff:                    packageObj.optionalDependencies[dependency] = replaceImpureVersionSpec(versionSpec);
                 }
             }
  -          
  +
             /* Write the fixed JSON file */
             fs.writeFileSync("package.json", JSON.stringify(packageObj));
           '';
  
positive.code:     let
        nodeDependencies = stdenv.mkDerivation {
          name = "node-dependencies-${name}-${version}";
          
          buildInputs = [ tarWrapper python nodejs ] ++ stdenv.lib.optional (stdenv.isLinux) utillinux ++ args.buildInputs or [];
          
          includeScript = includeDependencies { inherit dependencies; };
          passAsFile = [ "includeScript" ];
          
          buildCommand = ''
            mkdir -p $out/lib
            cd $out/lib
            source $includeScriptPath
            
            # Create fake package.json to make the npm commands work properly
            cat > package.json <<EOF
            {
  
negative.code:               "version": "${version}"
            }
            EOF
  
            # Patch the shebangs of the bundled modules to prevent them from
            # calling executables outside the Nix store as much as possible
            patchShebangs .
  
            export HOME=$PWD
            npm --registry http://www.example.com --nodedir=${nodeSources} ${npmFlags} ${stdenv.lib.optionalString production "--production"} rebuild
  
            ${stdenv.lib.optionalString (!dontNpmInstall) ''
              # NPM tries to download packages even when they already exist if npm-shrinkwrap is used.
              rm -f npm-shrinkwrap.json
  
              npm --registry http://www.example.com --nodedir=${nodeSources} ${npmFlags} ${stdenv.lib.optionalString production "--production"} install
            ''}
  
  