Make JSON encoding optional

This enables the generated javascript to do multipart MIME file uploads.

It is the user's responsibility to generate a valid body; e.g.:

    var fileObject = new File([blob], 'video.webm', {
        type: 'video/webm'
    });
    var formData = new FormData();
    formData.append('video', fileObject);

    postVideo(formData, onSuccess, onError);

Author: Andrew Cady

servant-js.cabal

@@ -47,7 +47,7 @@ library
                      , base-compat     >= 0.9
                      , charset         >= 0.3
                      , lens            >= 4
-                     , servant-foreign >= 0.9 && <0.12
+                     , servant-foreign >= 0.11.2 && <0.12
                      , servant         >= 0.9 && <0.15
                      , text            >= 1.2  && < 1.3
 

src/Servant/JS/Vanilla.hs

@@ -34,7 +34,7 @@ generateVanillaJSWith opts req = "\n" <>
  <> "  xhr.open('" <> decodeUtf8 method <> "', " <> url <> ", true);\n"
  <>    reqheaders
  <> "  xhr.setRequestHeader('Accept', 'application/json');\n"
- <> (if isJust (req ^. reqBody) then "  xhr.setRequestHeader('Content-Type', 'application/json');\n" else "")
+ <> (if isJust (req ^. reqBody) && (req ^. reqBodyIsJSON)  then "  xhr.setRequestHeader('Content-Type', 'application/json');\n" else "")
  <> "  xhr.onreadystatechange = function () {\n"
  <> "    var res = null;\n"
  <> "    if (xhr.readyState === 4) {\n"
@@ -79,7 +79,7 @@ generateVanillaJSWith opts req = "\n" <>
 
         dataBody =
           if isJust (req ^. reqBody)
-            then "JSON.stringify(body)"
+            then if (req ^. reqBodyIsJSON) then "JSON.stringify(body)" else "body"
             else "null"