Improve error handling by parsing GraphQL error messages

packages/vulcan-lib/lib/modules/errors.js

@@ -1,5 +1,57 @@
 /*
 
+Get whatever word is contained between the first two double quotes
+
+*/
+const getFirstWord = input => {
+  const parts = /"([^"]*)"/.exec(input);
+  if (parts === null) {
+    return null;
+   }
+   return parts[1];
+}
+
+/* 
+
+Parse a GraphQL error message
+
+Sample message: 
+
+"GraphQL error: Variable "$data" got invalid value {"meetingDate":"2018-08-07T06:05:51.704Z"}.
+In field "name": Expected "String!", found null.
+In field "stage": Expected "String!", found null.
+In field "addresses": Expected "[JSON]!", found null."
+
+*/
+
+const parseErrorMessage = message => {
+
+  // note: optionally add .slice(1) at the end to get rid of the first error, which is not that helpful
+  let fieldErrors = message.split('\n');
+
+  fieldErrors = fieldErrors.map(error => {
+    // field name is whatever is between the first to double quotes
+    const fieldName = getFirstWord(error);
+    if (error.includes('found null')) {
+      // missing field errors 
+      return {
+        id: 'errors.required',
+        path: fieldName,
+        properties: {
+          name: fieldName,
+        },
+      }
+    } else {
+      // other generic GraphQL errors
+      return { 
+        message: error
+      }
+    }
+  });
+  return fieldErrors;
+}
+/*
+
 Errors can have the following properties stored on their `data` property:
   - id: used as an internationalization key, for example `errors.required`
   - path: for field-specific errors inside forms, the path of the field with the issue
@@ -33,8 +85,8 @@ export const getErrors = error => {
         errors = [graphQLError.data];
       }
     } else {
-      // 4. there is no data object, just use raw error
-      errors = [graphQLError];
+      // 4. there is no data object, try to parse raw error message
+      errors = parseErrorMessage(graphQLError.message);
     }
   }
   return errors;