diff --git a/js/js.libraries/src/core/json.kt b/js/js.libraries/src/core/json.kt
index 335a1eb9068..5c9a56dbed9 100644
--- a/js/js.libraries/src/core/json.kt
+++ b/js/js.libraries/src/core/json.kt
@@ -15,4 +15,7 @@ library("jsonGet")
 fun Json.get(paramName : String) : Any? = js.noImpl
 
 library("jsonFromTuples")
-fun json(vararg pairs : Tuple2<String, Any?>) : Json = js.noImpl
\ No newline at end of file
+fun json(vararg pairs : Tuple2<String, Any?>) : Json = js.noImpl
+
+library("jsonAddProperties")
+fun Json.add(other : Json) : Json = js.noImpl
\ No newline at end of file