GraphQL: Error when iterating over undefined array

[douglasmuraoka]

Issue Description

TypeError: Cannot read property 'map' of undefined when iterating over an undefined array

Steps to reproduce

1. Create a custom class (named as "tests")
2. Create an Array field (named as "arr")
3. Leave this field value undefined (not null, not [])
4. Execute the following GraphQL query:

query {
  objects {
    tests {
      arr {
        ...on Element {
          value
        }
      }
    }
  }
}

Expected Results

GraphQL query should execute.

Actual Outcome

TypeError: Cannot read property 'map' of undefined
parseClassTypes:652

Environment Setup

• Server
  • parse-server version: 3.7.2
  • Localhost or remote server? localhost