[schema] Fix edge case where accessing type.preview would fail (#215)

sanity-io · Sep 29, 2017 · fa4109c · fa4109c
1 parent 8cd4340
commit fa4109c
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/packages/@sanity/schema/src/preview/guessPreviewConfig.js b/packages/@sanity/schema/src/preview/guessPreviewConfig.js
@@ -39,7 +39,8 @@ function resolveFileAssetPath(typeDef) {
   return fieldWithFileAsset ? `${fieldWithFileAsset.name}.asset` : undefined
 }
 
-export default function guessPreviewFields(objectTypeDef) {
+export default function guessPreviewFields(rawObjectTypeDef) {
+  const objectTypeDef = {fields: [], ...rawObjectTypeDef}
 
   const stringFieldNames = objectTypeDef.fields
     .filter(field => field.type === 'string')