In reply to @peter-lustig:matrix.org
but when I build locally with npm run build, then cd buildand run node ., everything just works

In reply to @lily:lily.flowers
can you share your derivation that you used to make the build dir?

devShells.${system}.default = pkgs.mkShell {
      buildInputs = with pkgs; [
        nodejs_20
      ];
    };
    packages.${system}.default = pkgs.buildNpmPackage {
      name = "build-my-application";
      src = ./.;
      npmDepsHash = "sha256-mTpjBKTIJkYVj2jrH5lF/n3Axceak4L60ZDQECQhGew=";
      installPhase = ''
        mkdir $out
        cp -r build/* $out
      '';
    };

In reply to @peter-lustig:matrix.org

devShells.${system}.default = pkgs.mkShell {
      buildInputs = with pkgs; [
        nodejs_20
      ];
    };
    packages.${system}.default = pkgs.buildNpmPackage {
      name = "build-my-application";
      src = ./.;
      npmDepsHash = "sha256-mTpjBKTIJkYVj2jrH5lF/n3Axceak4L60ZDQECQhGew=";
      installPhase = ''
        mkdir $out
        cp -r build/* $out
      '';
    };

In reply to @lily:lily.flowers
So I was meaning the actual like workspaces field in package.json

In reply to @lily:lily.flowers
what if you just installPhase = "cp -r build $out" instead of the mkdir and stuff?

In reply to @lily:lily.flowers
can you diff -r build /nix/store/xixmhd827wd95j6748xv3zyn5cf3kb9x-build-my-application from your local build?

do I maybe need to copy some additional stuff to $out Lily Foster ?

You will need the output directory, the project's package.json, and the production dependencies in node_modules to run the application. Production dependencies can be generated by copying the package.json and package-lock.json and then running npm ci --omit dev (you can skip this step if your app doesn't have any dependencies). You can then start your app with this command:

In reply to @peter-lustig:matrix.org
something seems to be completely different about them

In reply to @lily:lily.flowers
could you share at least a high-level overview of the differences? i mean do they just look different entirely when you ls each of them?