yarnBuildHook: init

pkgs/build-support/node/fetch-yarn-deps/default.nix

@@ -168,4 +168,11 @@ in
       description = "Install nodejs dependencies from an offline yarn cache produced by fetchYarnDeps";
     };
   } ./yarn-config-hook.sh;
+
+  yarnBuildHook = makeSetupHook {
+    name = "yarn-build-hook";
+    meta = {
+      description = "Run yarn build in buildPhase";
+    };
+  } ./yarn-build-hook.sh;
 }

pkgs/build-support/node/fetch-yarn-deps/yarn-build-hook.sh

@@ -0,0 +1,25 @@
+yarnBuildHook() {
+    runHook preBuild
+    echo "Executing yarnBuildHook"
+
+    if [ -z "${yarnBuildScript-}" ]; then
+        yarnBuildScript="build"
+    fi
+
+    if ! type node > /dev/null 2>&1 ; then
+        echo yarnConfigHook WARNING: a node interpreter was not added to the \
+            build, and is probably required to run \'yarn $yarnBuildHook\'. \
+            A common symptom of this is getting \'command not found\' errors \
+            for Nodejs related tools.
+    fi
+
+    yarn --offline "$yarnBuildScript" \
+        $yarnBuildFlags "${yarnBuildFlagsArray[@]}"
+
+    echo "finished yarnBuildHook"
+    runHook postBuild
+}
+
+if [[ -z "${dontYarnBuild-}" && -z "${buildPhase-}" ]]; then
+    buildPhase=yarnBuildHook
+fi

pkgs/top-level/all-packages.nix

@@ -987,6 +987,7 @@ with pkgs;
     fixup-yarn-lock
     prefetch-yarn-deps
     yarnConfigHook
+    yarnBuildHook
     fetchYarnDeps;
 
   find-cursor = callPackage ../tools/X11/find-cursor { };