Non-null
Also written: non-nullable, !
A type marked with `!`, such as `String!`, which promises the field is never `null`. If a resolver returns null anyway, GraphQL reports an error and nulls the parent.
Also written: non-nullable, !
A type marked with `!`, such as `String!`, which promises the field is never `null`. If a resolver returns null anyway, GraphQL reports an error and nulls the parent.