fix(FallbackAlgorithm): If before cursor provided, limit should not exceed its offset

Author: nodkz

src/__tests__/connectionResolver-test.js

@@ -649,5 +649,18 @@ describe('connectionResolver', () => {
       expect(next).deep.property('edges.0.node.id')
         .equals(result.edges[2].node.id);
     });
+
+    it('should reduce limit if reach cursor offset', async () => {
+      const result = await connectionResolver.resolve({
+        args: {
+          sort: { name: 1 },
+          before: dataToCursor(2),
+          first: 5,
+        },
+      });
+      expect(result).deep.property('edges').to.have.length(2);
+      expect(result).deep.property('edges.0.node.id').equals(1);
+      expect(result).deep.property('edges.1.node.id').equals(2);
+    });
   });
 });

src/connectionResolver.js

@@ -297,9 +297,10 @@ export function prepareLimitSkipFallback(
     newSkip = skip - beforeSkip;
     if (newSkip < 0) {
       newSkip = 0;
-      newLimit = limit + newSkip;
-      if (newLimit < 0) {
-        newLimit = 0;
+      newLimit = limit;
+      // offset 0, so limit should not exceed offset in cursor, otherwise it returns again this record
+      if (newLimit > beforeSkip) {
+        newLimit = beforeSkip;
       }
     }
   } else if (afterSkip) {