Reducers should be able to clean non-existent nested fields and not fail

lib/query/reducers/lib/cleanReducerLeftovers.js

@@ -43,7 +43,7 @@ function cleanNestedFields(parts, results) {
     if (parts.length === 1) {
 
         results.forEach(result => {
-            if (fieldName !== '_id') {
+            if (_.isObject(result) && fieldName !== '_id') {
                 delete result[fieldName];
             }
         });
@@ -55,7 +55,7 @@ function cleanNestedFields(parts, results) {
     cleanNestedFields(parts, results.map(result => result[fieldName]));
 
     results.forEach(result => {
-        if (_.keys(result[fieldName]).length === 0) {
+        if (_.isObject(result[fieldName]) && _.keys(result[fieldName]).length === 0) {
             if (fieldName !== '_id') {
                 delete result[fieldName];
             }

lib/query/testing/bootstrap/posts/links.js

@@ -42,4 +42,17 @@ Posts.addLinks({
             }
         }
     }
+});
+
+Posts.addReducers({
+    reducerNonExistentNestedField: {
+        body: {
+            nested: {
+                title: 1,
+            }
+        },
+        reduce(object) {
+            return object.nested ? object.nested.title : 'null';
+        }
+    },
 });

lib/query/testing/reducers.server.test.js

@@ -267,4 +267,15 @@ describe('Reducers', function() {
         const data = query.fetch();
         assert.isTrue(data.length > 0);
     });
+
+    it('Should allow non-existent nested fields while cleaning', function() {
+        const query = createQuery({
+            posts: {
+                reducerNonExistentNestedField: 1,
+            },
+        });
+
+        const data = query.fetch({limit: 1});
+        assert.equal(data[0].reducerNonExistentNestedField, 'null');
+    });
 });