revert: "rm nix/agent-js/agent-js.nix, which is not used by anything (#1008)"

default.nix

@@ -14,6 +14,7 @@ rec {
 
   # Agents in varous languages
   agent-js-monorepo = pkgs.agent-js-monorepo;
+  agent-js = import ./nix/agent-js/agent-js.nix { inherit system pkgs; };
 
   # Bootstrap frontend.
   bootstrap-js = import ./nix/agent-js/bootstrap-js.nix { inherit system pkgs; };

nix/agent-js/agent-js.nix

@@ -0,0 +1,37 @@
+{ pkgs ? import ../. { inherit system; }, system ? builtins.currentSystem }:
+pkgs.stdenv.mkDerivation {
+  name = "agent-js-monorepo-package-agent";
+  src = "${pkgs.agent-js-monorepo}";
+  outputs = [
+    "out"
+    "lib"
+  ];
+  buildInputs = [
+    pkgs.nodejs
+    pkgs.agent-js-monorepo
+  ];
+  configurePhase = ''
+    export HOME=$(mktemp -d)
+  '';
+  buildPhase = ''
+    cd packages/agent
+    echo "calling npm pack"
+    npm pack
+    cd -
+  '';
+  installPhase = ''
+    # $out: everything
+    mkdir -p $out
+    cp -R ${pkgs.agent-js-monorepo.agent}/* $out/
+    cp -R packages/agent/dfinity-agent*.tgz $out/
+
+    # $lib/node_modules: node_modules dir that must be resolvable by npm
+    #   for future build steps to work (e.g. at ../../node_modules)
+    mkdir -p $lib
+    agent_node_modules="${pkgs.agent-js-monorepo}/packages/agent/node_modules"
+    if test -d "$agent_node_modules"; then
+      cp -R "$agent_node_modules" $lib;
+    fi
+
+  '';
+}

nix/sources.json

@@ -15,7 +15,7 @@
     "agent-js-monorepo": {
         "ref": "next",
         "repo": "ssh://git@github.com/dfinity-lab/agent-js",
-        "rev": "ccea79546e273892041b3863cf7a5e4ad51c2f07",
+        "rev": "87626f7a7820358143eeb0e4defa223396632923",
         "type": "git"
     },
     "bats-support": {
@@ -44,9 +44,9 @@
         "type": "git"
     },
     "ic-ref": {
+        "branch": "release-0.10",
         "repo": "ssh://git@github.com/dfinity-lab/ic-ref",
         "rev": "7d453c4b09f78b3fa1f06df6a3ff00e51b11ca3e",
-        "branch": "release-0.10",
         "type": "git"
     },
     "motoko": {