Use

parseInstanceData comes in handy when dealing with an irregular API that can be improved with data transformation.

Suppose a request to /services/todos returns:

{
  baseUrl: "/proxy/share",
  todo: {
    id: 0,
    name: "dishes",
    friendFaceUrl: "friendface?id=0",
    fiddlerUrl: "fiddler?id=0"
  }
}

The baseUrl property is meta-data that needs to be incorporated into the instance data. One way to deal with this is:

connect([
  require("can-connect/data/parse/parse"),
  require("can-connect/data/url/url")
],{
  parseInstanceProp: "todo",
  parseInstanceData(responseData) {
    ['friendFaceUrl', 'fiddlerUrl'].map(urlProp => {
      responseData.todo[urlProp] = [
        responseData.baseUrl,
        responseData.todo[urlProp]
      ].join('/');
    });

    return responseData;
  }
})

This results in an object like:

{
  id: 0,
  name: "dishes",
  friendFaceUrl: "/proxy/share/friendface?id=0",
  fiddlerUrl: "/proxy/share/fiddler?id=0"
}