bug with localization plugin

src/localization/plugin.js

@@ -138,7 +138,7 @@ module.exports = function localizationPlugin(schema, options) {
       })
       .set(function (value) {
         // multiple locales are set as an object
-        if (typeof value === 'object' && !Array.isArray(value)) {
+        if (value && typeof value === 'object' && !Array.isArray(value)) {
           const { locales } = this.schema.options.localization;
           locales.forEach((locale) => {
             if (!value[locale]) {

src/responses/formatError.js

@@ -1,14 +1,30 @@
 const formatErrorResponse = (incoming, source) => {
   switch (source) {
     case 'mongoose':
+
+      if (incoming && incoming.errors) {
+        return {
+          errors: Object.keys(incoming.errors).reduce((acc, key) => {
+            acc.push({
+              message: incoming.errors[key].message,
+            });
+            return acc;
+          }, []),
+        };
+      }
+
+      // If the Mongoose error does not get returned with incoming && incoming.errors,
+      // it's of a type that we really don't know how to handle. Sometimes this means a TypeError,
+      // which we might be able to manipulate to get the error message itself and send that back.
+
       return {
-        errors: Object.keys(incoming.errors).reduce((acc, key) => {
-          acc.push({
-            message: incoming.errors[key].message,
-          });
-          return acc;
-        }, []),
+        errors: [
+          {
+            message: 'An unknown error occurred.',
+          },
+        ],
       };
+
     case 'APIError':
       return {
         errors: [