How to use the cloudform-types.Fn.Split function in cloudform-types

public makeElasticsearchDataSource() {
        const logicalName = ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID
        return new AppSync.DataSource({
            ApiId: Fn.GetAtt(ResourceConstants.RESOURCES.GraphQLAPILogicalID, 'ApiId'),
            Name: logicalName,
            Type: 'AMAZON_ELASTICSEARCH',
            ServiceRoleArn: Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchAccessIAMRoleLogicalID, 'Arn'),
            ElasticsearchConfig: {
                AwsRegion: Fn.Select(3, Fn.Split(':', Fn.GetAtt(logicalName, 'DomainArn'))),
                Endpoint:
                    Fn.Join('', [
                        'https://',
                        Fn.GetAtt(logicalName, 'DomainEndpoint')
                    ])
            }
        }).dependsOn(ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID)
    }

'functions',
          Fn.Join('.', [ResourceConstants.RESOURCES.ElasticsearchStreamingLambdaFunctionLogicalID, 'zip']),
        ]),
      },
      FunctionName: this.joinWithEnv('-', [
        Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchStreamingFunctionName),
        Fn.GetAtt(ResourceConstants.RESOURCES.GraphQLAPILogicalID, 'ApiId'),
      ]),
      Handler: Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchStreamingLambdaHandlerName),
      Role: Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchStreamingLambdaIAMRoleLogicalID, 'Arn'),
      Runtime: Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchStreamingLambdaRuntime),
      Layers: [Fn.FindInMap('LayerResourceMapping', Fn.Ref('AWS::Region'), 'layerRegion')],
      Environment: {
        Variables: {
          ES_ENDPOINT: Fn.Join('', ['https://', Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID, 'DomainEndpoint')]),
          ES_REGION: Fn.Select(3, Fn.Split(':', Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID, 'DomainArn'))),
          DEBUG: Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchDebugStreamingLambda),
        },
      },
    }).dependsOn([
      ResourceConstants.RESOURCES.ElasticsearchStreamingLambdaIAMRoleLogicalID,
      ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID,
    ]);
  }

])
            },
            FunctionName: this.joinWithEnv("-", [
                Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchStreamingFunctionName),
                Fn.GetAtt(ResourceConstants.RESOURCES.GraphQLAPILogicalID, 'ApiId'),
            ]),
            Handler: Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchStreamingLambdaHandlerName),
            Role: Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchStreamingLambdaIAMRoleLogicalID, 'Arn'),
            Runtime: Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchStreamingLambdaRuntime),
            Environment: {
                Variables: {
                    ES_ENDPOINT: Fn.Join('', [
                        'https://',
                        Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID, 'DomainEndpoint')
                    ]),
                    ES_REGION: Fn.Select(3, Fn.Split(':', Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID, 'DomainArn'))),
                    DEBUG: Fn.Ref(ResourceConstants.PARAMETERS.ElasticsearchDebugStreamingLambda)
                }
            }
        }).dependsOn([
            ResourceConstants.RESOURCES.ElasticsearchStreamingLambdaIAMRoleLogicalID,
            ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID
        ])
    }

public makeElasticsearchDataSource() {
    const logicalName = ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID;
    return new AppSync.DataSource({
      ApiId: Fn.GetAtt(ResourceConstants.RESOURCES.GraphQLAPILogicalID, 'ApiId'),
      Name: logicalName,
      Type: 'AMAZON_ELASTICSEARCH',
      ServiceRoleArn: Fn.GetAtt(ResourceConstants.RESOURCES.ElasticsearchAccessIAMRoleLogicalID, 'Arn'),
      ElasticsearchConfig: {
        AwsRegion: Fn.Select(3, Fn.Split(':', Fn.GetAtt(logicalName, 'DomainArn'))),
        Endpoint: Fn.Join('', ['https://', Fn.GetAtt(logicalName, 'DomainEndpoint')]),
      },
    }).dependsOn(ResourceConstants.RESOURCES.ElasticsearchDomainLogicalID);
  }