diff --git a/application/source/data/transformer.mjs b/application/source/data/transformer.mjs
index fbdefeca8c471b691e66a83a0add042c905041fa..45945146bbd4e6537f00f877c30776be0a8ad670 100644
--- a/application/source/data/transformer.mjs
+++ b/application/source/data/transformer.mjs
@@ -406,6 +406,11 @@ function transform(value) {
                     throw new Error("missing key parameter");
                 }
                 
+                if (isString(key)&&key.trim()==="") {
+                    concat += key;
+                    continue;
+                }
+                
                 if (!pf2.exists(key)) {
                     concat += key;
                     continue;
diff --git a/development/test/cases/data/transformer.mjs b/development/test/cases/data/transformer.mjs
index 8b4c3321d8262e07d377b41bea7835736b39f049..f2991d44755830e9383759b5eb98ca80df55ea22 100644
--- a/development/test/cases/data/transformer.mjs
+++ b/development/test/cases/data/transformer.mjs
@@ -28,6 +28,9 @@ describe('Transformer', function () {
 
         [
             ['concat:a.b.c:test:a.b.d', {a: {b: {c: 4, d: 6}}}, "4test6"],
+            ['concat:a.b.c:\\ \\ :a.b.d', {a: {b: {c: 4, d: 6}}}, "4  6"],
+            ['concat:a.b.c:,:a.b.d', {a: {b: {c: 4, d: 6}}}, "4,6"],
+            ['concat:a.b.c:,:\\ :a.b.d', {a: {b: {c: 4, d: 6}}}, "4, 6"],
             ['??:a', null, 'a'],
             ['??:a', undefined, 'a'],
             ['??:a', 'true', 'true'],