Spoke too soon; that doesn't work. For example:
> foo = Json.Encode.string "[]"
"[]" : Json.Encode.Value
> bar = Json.Decode.decodeValue (Json.Decode.list Json.Decode.string) foo
Err "Expecting a List but instead got: \"[]\""
: Result.Result String (List String)
On Friday, July 29, 2016 at 3:10:01 PM UTC-4, Paul Blair wrote:
>
> To answer my own question -- it looks like Native.Json has an identity
> function which does just what I want, but which I can't import. However, it
> also looks like many of Json.Encode's functions just call
> Native.Json.identity. So this works:
>
> data = Encode.string complicatedNestedJson
>
>
>
> On Friday, July 29, 2016 at 2:52:32 PM UTC-4, Paul Blair wrote:
>>
>> I'm using the nested Elm architecture pattern in an application. The
>> nested components respond to messages coming in on a port. The messages are
>> handled by the top-level component before being handed on to the nested
>> components. So the outer data structure looks something like this:
>>
>> type alias FromServer =
>> { message_type: MessageType
>> , data: Json.Decode.Value
>> }
>>
>> The data field is a Json.Decode.Value because the top-level component
>> doesn't know about the message types defined by the nested components; it
>> does a lookup on the incoming message type and decides to which inner
>> component it will forward the message. So the top level looks like this:
>>
>> subscriptions : Model.Model -> Sub Message
>> subscriptions model =
>> theIncomingPort toMessage
>>
>>
>> toMessage : FromServer -> Message
>> toMessage incoming =
>> case Dict.get incoming.message_type componentDictionary of
>> Just MyInnerComponent ->
>> InnerComponentModule.toMessage incoming |>
>> MyInnerComponentMessageWrapper
>> Nothing ->
>> ...
>>
>> The inner component's toMessage function also uses the message_type field
>> to choose the decoder to apply to the Json.Decode.Value in the data field.
>>
>> I want to test the inner component's toMessage function. This means that
>> I need to create a FromServer record with the data contained in a
>> Json.Decode.Value -- ideally created from a Json string.
>>
>> However, from what I can tell the only way to create this kind of raw
>> Json.Decode.Value is by passing the string in through a port. This seems
>> like a pretty complicated way to set up a test. Is there some other way to
>> accomplish this?
>>
>>
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