I am having this simple program using Affjax and
import Network.HTTP.Affjax as Affjax
import Control.Monad.Aff (launchAff)
test1 = launchAff $ do Affjax.get "/api"
this gives me the following error
58 test1 = launchAff $ do Affjax.get "/api"
No type class instance was found for
The instance head contains unknown type variables. Consider adding a type annotation.
in value declaration test1
where _0 is an unknown type
I understand that
Respondable needs to be be defined here but I really dont get how to do it exactly.
Any help is greatly appreciated.
You'll need to annotate your test1 function to let the compiler know what you expect to get back from that ajax call.
test1 = launchAff do Affjax.get "/api" :: Affjax _ Foreign
You can choose any one of these instances for your return type, or if you expect your own datatype to be returned, write a
Respondable instance for it.
EDIT: I edited the source code. The provided codesnippet isn't very useful though, since you're not doing anything with the AJAX response. Since
Affjax operates inside
Aff you can use do notation to bind the result of the
GET call to a variable and proceed to use it from there.