Using SwaggerEditorBundle download yaml file locally

I have included Swagger UI in my angular application using  SwaggerEditorBundle. I am trying to download YAML file using SwaggerEditorBundle.specActions.download(). 

I m getting below error 

n {name: "YAMLException", reason: "end of the stream or a document separator is expected", mark: I, message: "end of the stream or a document separator is expec