Add helper: productTypeForTargettype()
diff --git a/lib/pbxProject.js b/lib/pbxProject.js
index d6cb5f3..ebc7715 100644
--- a/lib/pbxProject.js
+++ b/lib/pbxProject.js
@@ -1165,6 +1165,24 @@
     if (str) return str.replace(/^"(.*)"$/, "$1");
 }
 
+function producttypeForTargettype (targetType) {
+
+    PRODUCTTYPE_BY_TARGETTYPE = {
+            application: 'com.apple.product-type.application',
+            app_extension: 'com.apple.product-type.app-extension',
+            bundle: 'com.apple.product-type.bundle',
+            command_line_tool: 'com.apple.product-type.tool',
+            dynamic_library: 'com.apple.product-type.library.dynamic',
+            framework: 'com.apple.product-type.framework',
+            static_library: 'com.apple.product-type.library.static',
+            unit_test_bundle: 'com.apple.product-type.bundle.unit-test',
+            watch_app: 'com.apple.product-type.application.watchapp',
+            watch_extension: 'com.apple.product-type.watchkit-extension'
+        };
+
+    return PRODUCTTYPE_BY_TARGETTYPE[targetType]
+}
+
 pbxProject.prototype.getFirstProject = function() {
 
     // Get pbxProject container