Swap part1 and part2

advanced/part1/src/Viewer/Cred.elm

@@ -1,20 +1,4 @@
-module Viewer.Cred exposing (Cred, addHeader, addHeaderIfAvailable, decoder, encodeToken, username)
-
-{-| The authentication credentials for the Viewer (that is, the currently logged-in user.)
-
-This includes:
-
-  - The cred's Username
-  - The cred's authentication token
-
-By design, there is no way to access the token directly as a String.
-It can be encoded for persistence, and it can be added to a header
-to a HttpBuilder for a request, but that's it.
-
-This token should never be rendered to the end user, and with this API, it
-can't be!
-
--}
+module Viewer.Cred exposing (Cred, addHeader, addHeaderIfAvailable, decoder, encodeToken)
 
 import HttpBuilder exposing (RequestBuilder, withHeader)
 import Json.Decode as Decode exposing (Decoder)
@@ -23,30 +7,21 @@ import Json.Encode as Encode exposing (Value)
 import Username exposing (Username)
 
 
-{-| The authentication token for the currently logged-in user.
-
-The token records the username associated with this token, which you can ask it for.
-
-By design, there is no way to access the token directly as a String. You can encode it for persistence, and you can add it to a header to a HttpBuilder for a request, but that's it.
-
--}
-
-
 
 -- TYPES
 
 
-type Cred
-    = Cred Username String
-
-
-
--- INFO
-
-
-username : Cred -> Username
-username (Cred val _) =
-    val
+type alias Cred =
+    -- 👉 TODO make Cred an opaque type, then fix the resulting compiler errors.
+    -- Afterwards, it should no longer be possible for any other module to access
+    -- this `token` vale directly!
+    --
+    -- 💡 HINT: Other modules still depend on being able to access the
+    -- `username` value. Expand this module's API to expose a new way for them
+    -- to access the `username` without also giving them access to `token`.
+    { username : Username
+    , token : String
+    }
 
 
 
@@ -65,14 +40,14 @@ decoder =
 
 
 encodeToken : Cred -> Value
-encodeToken (Cred _ str) =
-    Encode.string str
+encodeToken cred =
+    Encode.string cred.token
 
 
 addHeader : Cred -> RequestBuilder a -> RequestBuilder a
-addHeader (Cred _ str) builder =
+addHeader cred builder =
     builder
-        |> withHeader "authorization" ("Token " ++ str)
+        |> withHeader "authorization" ("Token " ++ cred.token)
 
 
 addHeaderIfAvailable : Maybe Cred -> RequestBuilder a -> RequestBuilder a