>     at VariableDeclarator.bind (file:///build/2rdr2hwic3kd9pwpgp32s206yh5kqwhs-source/node_modules/rollup/dist/es/shared/node-entry.js:4639:23)
       >
       > ERROR: `npm build` failed

Is this some nix issue again?

I can build the project fine with npm run build

My build script (left the hash out for abbreviation):

packages.${system}.default = pkgs.buildNpmPackage {
      name = "project-build";
      src = ./.;
      installPhase = ''
        mkdir $out
        cp -r build/* $out
        cp package.json $out
        cp -r node_modules $out
      '';
    };
  };