Make DataSource.Port error catchable.

examples/end-to-end/app/Route/Fetcher.elm

@@ -100,6 +100,7 @@ data routeParams =
         (DataSource.Port.get "getItems"
             Encode.null
             (Decode.list Decode.string)
+            |> DataSource.throw
             |> DataSource.map
                 (\items ->
                     Server.Response.render
@@ -127,6 +128,7 @@ action routeParams =
                         DataSource.Port.get "addItem"
                             (Encode.string newItem)
                             (Decode.list Decode.string)
+                            |> DataSource.throw
                             |> DataSource.map
                                 (\_ ->
                                     Server.Response.render ActionData
@@ -136,6 +138,7 @@ action routeParams =
                         DataSource.Port.get "deleteAllItems"
                             Encode.null
                             (Decode.list Decode.string)
+                            |> DataSource.throw
                             |> DataSource.map
                                 (\_ ->
                                     Server.Response.render ActionData

examples/end-to-end/app/Route/Index.elm

@@ -53,7 +53,7 @@ data : DataSource Throwable Data
 data =
     DataSource.map2 Data
         (DataSource.File.rawFile "greeting.txt" |> DataSource.throw)
-        (DataSource.Port.get "hello" (Encode.string "Jane") Decode.string)
+        (DataSource.Port.get "hello" (Encode.string "Jane") Decode.string |> DataSource.throw)
 
 
 head :

src/DataSource/Port.elm

@@ -14,6 +14,7 @@ module DataSource.Port exposing
 import DataSource
 import DataSource.Http
 import DataSource.Internal.Request
+import Exception exposing (Catchable)
 import Json.Decode exposing (Decoder)
 import Json.Encode as Encode
 
@@ -79,7 +80,7 @@ prefer to add ANSI color codes within the error string in an exception and it wi
 As with any JavaScript or NodeJS code, avoid doing blocking IO operations. For example, avoid using `fs.readFileSync`, because blocking IO can slow down your elm-pages builds and dev server.
 
 -}
-get : String -> Encode.Value -> Decoder b -> DataSource.DataSource Error b
+get : String -> Encode.Value -> Decoder b -> DataSource.DataSource (Catchable Error) b
 get portName input decoder =
     DataSource.Internal.Request.request
         { name = "port"
@@ -93,7 +94,7 @@ get portName input decoder =
             decoder
                 |> DataSource.Http.expectJson
         }
-        |> DataSource.onError (\_ -> DataSource.fail Error)
+        |> DataSource.onError (\_ -> DataSource.fail (Exception.Catchable Error "Port Error - TODO better error message"))
 
 
 {-| -}