[graphql-fixtures] Graphql fixtures/seed collision fix

packages/graphql-fixtures/src/fill.ts

@@ -495,14 +495,14 @@ function randomEnumValue(enumType: GraphQLEnumType) {
 }
 
 function seedFromKeypath(keypath: string[]) {
-  return keypath.reduce<number>((sum, key) => sum + seedFromKey(key), 0);
+  return keypath.reduce<number>((sum, key) => hashCode(key, sum), 0);
 }
 
-function seedFromKey(key: string) {
-  return [...key].reduce<number>(
-    (sum, character) => sum + character.charCodeAt(0),
-    0,
-  );
+function hashCode(data: string, initialHash = 0) {
+  let newHash = initialHash;
+  for (let i = 0; i < data.length; i++)
+    newHash = (Math.imul(31, newHash) + data.charCodeAt(i)) | 0;
+  return newHash;
 }
 
 export function list<T = {}, Data = {}, Variables = {}, DeepPartial = {}>(

packages/graphql-fixtures/src/tests/fill.test.ts

@@ -1324,6 +1324,48 @@ describe('createFiller()', () => {
         people: [{name: expect.any(String)}, {name: 'Chris'}],
       });
     });
+
+    it('has no duplicate ids in nested fields', () => {
+      const fill = createFillerForSchema(`
+        type Pet {
+          id: ID!
+        }
+
+        type Person {
+          pets: [Pet]!
+        }
+
+        type Query {
+          people: [Person!]!
+        }
+      `);
+
+      const document = createDocument<
+        {people: {pets: {id: string}[]}[]},
+        {people?: {pets?: {id?: string | null}[] | null}[] | null}
+      >(`
+        query Details {
+          people {
+            pets {
+              id
+            }
+          }
+        }
+      `);
+
+      const result = fill(document, {
+        people: Array.from(Array(100)).map(() => ({
+          pets: Array.from(Array(100)).map(() => ({})),
+        })),
+      });
+
+      const allIds = result.people
+        .flatMap((person) => person.pets)
+        .map((pet) => pet.id);
+
+      const allIdSet = new Set(allIds);
+      expect(allIdSet.size).toBe(allIds.length);
+    });
   });
 });