/**
* This method looks up the field on the given type defintion.
* It has special casing for the two introspection fields, __schema
* and __typename. __typename is special because it can always be
* queried as a field, even in situations where no other fields
* are allowed, like on a Union. __schema could get automatically
* added to the query type, but that would require mutating type
* definitions, which would cause issues.
*/
func getFieldDef(schema types.GraphQLSchema, parentType *types.GraphQLObjectType, fieldName string) *types.GraphQLFieldDefinition {
if parentType == nil {
return nil
}
if fieldName == types.SchemaMetaFieldDef.Name &&
schema.GetQueryType() == parentType {
return types.SchemaMetaFieldDef
}
if fieldName == types.TypeMetaFieldDef.Name &&
schema.GetQueryType() == parentType {
return types.TypeMetaFieldDef
}
if fieldName == types.TypeNameMetaFieldDef.Name {
return types.TypeNameMetaFieldDef
}
return parentType.GetFields()[fieldName]
}
