[Fix #712] Describe merge behaviour for non object

specification.md

@@ -439,7 +439,7 @@ The second way would be to directly filter only the "veggie like" vegetables wit
 | fromStateData | Workflow expression that filters state data that can be used by the action | string | no |
 | useResults | If set to `false`, action data results are not added/merged to state data. In this case 'results' and 'toStateData' should be ignored. Default is `true`. | boolean | no |
 | results | Workflow expression that filters the actions data results | string | no |
-| toStateData | Workflow expression that selects a state data element to which the action results should be added/merged into. If not specified denotes the top-level state data element | string | no |
+| toStateData | Workflow expression that selects a state data element to which the action results should be added/merged into. If not specified denotes the top-level state data element. In case it is not specified and the result of the action is not an object, that result should be merged as value of `response` key. If that `response` key already exist in the model, its value will be overwritten. | string | no |
 
 <details><summary><strong>Click to view example definition</strong></summary>
 <p>
@@ -565,6 +565,27 @@ into. With this, after our action executes the state data would be:
 }
 ```
 
+To illustrate merge of not json both object, let`s assume that, in previous example, the action definition is at follows
+
+```json
+"actions":[
+ {
+ "name": "fetch_only_pasta",
+ "functionRef": "breadAndPastaTypesFunction",
+ "actionDataFilter": {
+ "results": "${ .pasta[1] ]",
+ }
+ }
+ ]
+}
+```
+Since there is not `toStateData` and the result is not a json object but an string, the state would be
+
+```json
+{
+ "response": "spaghetti"
+}
+```
 In the case action results should not be added/merged to state data, we can set the `useResults` property to `false`.
 In this case, the `results` and `toStateData` properties should be ignored, and nothing is added/merged to state data.
 If `useResults` is not specified (or it's value set to `true`), action results, if available, should be added/merged to state data.