Check that soapbox.json is really an object before importing, fixes #376

app/soapbox/actions/soapbox.js

@@ -40,8 +40,9 @@ export function fetchSoapboxConfig() {
 
 export function fetchSoapboxJson() {
   return (dispatch, getState) => {
-    api(getState).get('/instance/soapbox.json').then(response => {
-      dispatch(importSoapboxConfig(response.data));
+    api(getState).get('/instance/soapbox.json').then(({ data }) => {
+      if (!isObject(data)) throw 'soapbox.json failed';
+      dispatch(importSoapboxConfig(data));
     }).catch(error => {
       dispatch(soapboxConfigFail(error));
     });
@@ -56,12 +57,14 @@ export function importSoapboxConfig(soapboxConfig) {
 }
 
 export function soapboxConfigFail(error) {
-  if (!error.response) {
-    console.error('Unable to obtain soapbox configuration: ' + error);
-  }
   return {
     type: SOAPBOX_CONFIG_REQUEST_FAIL,
     error,
     skipAlert: true,
   };
 }
+
+// https://stackoverflow.com/a/46663081
+function isObject(o) {
+  return o instanceof Object && o.constructor === Object;
+}