Scan results are not being filtered correctly in response mapping

Question

I have a simple test table with user data with the following schema

```
type GlobalUsers {
	userid: String!
	firstname: String
	lastname: String
	email: AWSEmail
	phone: AWSPhone
	public: Boolean
}
```

The listGlobalUsers query with an unfiltered response mapping returns

```
{
  "data": {
    "listGlobalUsers": {
      "items": [
        {
          "userid": "janedoe",
          "email": "jane.doe@gmail.com",
          "phone": "12345678901"
        },
        {
          "userid": "johndoe",
          "email": "john.doe@gmail.com",
          "phone": "12345678901"
        }
      ]
    }
  }
}
```

If I modify the response template to filter on items marked as public

```
#set($publicRecords = [])
#foreach($item in $ctx.result.items)
    #if($item.public == true)
        #set($added = $publicRecords.add($item))
    #end
#end
$utils.toJson($publicRecords)
```

The query results are always null

```
{
  "data": {
    "listGlobalUsers": {
      "items": null
    }
  }
}
```

I wonder if I have something configured incorrectly because the results are always null, even if I remove the condition and add all items to $publicRecords

Answer

I was able to get it to work by setting the value of $ctx.result.items to $publicRecords  
  
The issue was caused by the structure of the result output. Do note that this response template is one of the example templates in the AppSync resolver UI, so it should probably be corrected.

```
#set($publicRecords = [])
#foreach($item in $ctx.result.items)
    #if($item.public == true)
        #set($added = $publicRecords.add($item))
    #end
#end
#set($ctx.result.items = $publicRecords)
$utils.toJson($ctx.result)
```

Edited by: raz92 on Jun 26, 2019 4:42 PM

Scan results are not being filtered correctly in response mapping

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