Patch generated js to work with non-json onError

See haskell-servant/servant-js#43

README.md

@@ -31,3 +31,8 @@ You'll need `libpcre3-dev` + `libmariadbclient-dev` (this is what they're called
 
 This build is in place so that you can easily run a "dev" server afterwards, refer to [Running](#Running).
 Building it on your machine might cause a `libc` mismatch between what is in the "deploy" image.
+
+## Modifications to js query functions
+
+Since servant doesn't return json-encoded values for errors (it's plaintext) the js functions need to be modified not to attempt
+to parse the error body as json.

js/queries.js

@@ -15,12 +15,7 @@ const getApiTask = function (backendUrl, onSuccess, onError) {
         }
         if (res) onSuccess(res)
       } else {
-        try {
-          res = JSON.parse(xhr.responseText)
-        } catch (e) {
-          onError(e)
-        }
-        if (res) onError(res)
+        if (xhr.responseText) onError(xhr.responseText)
       }
     }
   }
@@ -45,12 +40,7 @@ const postApiTask = function (backendUrl, body, onSuccess, onError) {
         }
         if (res) onSuccess(res)
       } else {
-        try {
-          res = JSON.parse(xhr.responseText)
-        } catch (e) {
-          onError(e)
-        }
-        if (res) onError(res)
+        if (xhr.responseText) onError(xhr.responseText)
       }
     }
   }
@@ -75,12 +65,7 @@ const postApiSubmit = function (backendUrl, body, onSuccess, onError) {
         }
         if (res) onSuccess(res)
       } else {
-        try {
-          res = JSON.parse(xhr.responseText)
-        } catch (e) {
-          onError(e)
-        }
-        if (res) onError(res)
+        if (xhr.responseText) onError(xhr.responseText)
       }
     }
   }