Koa response reported an error.

  node.js, question

Koa for the first time, all kinds of chaos. . .

In the database insert callback response, but reported the wrong, this is how to return a responsibility ah, how can have a response?

This error indicates that the data has been returned, but attempts are still being made to continue writing.
It is suggested to cook the generator before playing koa. This article is good, you can have a look at it.
http://blog.stevensanderson.com/2013/12/21/experiments-with-koa-and-ja …