fix(visitor-plugin-common): avoid reading from null values

dotansimha · Oct 17, 2023 · ea66985 · ea66985
1 parent 04d8781
commit ea66985
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/.changeset/perfect-forks-flash.md b/.changeset/perfect-forks-flash.md
@@ -0,0 +1,5 @@
+---
+'@graphql-codegen/visitor-plugin-common': patch
+---
+
+Avoid reading from null values when selection sets only contain fragments.
diff --git a/packages/plugins/other/visitor-plugin-common/src/selection-set-to-object.ts b/packages/plugins/other/visitor-plugin-common/src/selection-set-to-object.ts
@@ -714,7 +714,6 @@ export class SelectionSetToObject<Config extends ParsedDocumentsConfig = ParsedD
     return (
       Object.keys(grouped)
         .map(typeName => {
-          const hasUnions = grouped[typeName].filter(s => typeof s !== 'string' && s.union).length > 0;
           const relevant = grouped[typeName].filter(Boolean);
 
           if (relevant.length === 0) {
@@ -729,6 +728,8 @@ export class SelectionSetToObject<Config extends ParsedDocumentsConfig = ParsedD
             })
             .join(' & ');
 
+          const hasUnions = grouped[typeName].filter(s => typeof s !== 'string' && s.union).length > 0;
+
           return relevant.length > 1 && !hasUnions ? `( ${res} )` : res;
         })
         .filter(Boolean)