fix(modelgen): remove timestamps if defined null in @model (#355)

Author: AaronZyLee

packages/appsync-modelgen-plugin/src/__tests__/visitors/appsync-visitor.test.ts

@@ -680,6 +680,21 @@ describe('AppSyncModelVisitor', () => {
       const updatedAtField = postFields.find(field => field.name === 'updatedOn');
       expect(updatedAtField).toMatchObject(updatedAtFieldObj);
     });
+    it('should not generate timestamp fields if "timestamps:null" is defined in @model', () => {
+      const schema = /* GraphQL */ `
+        type Post @model(timestamps: null) {
+          id: ID!
+        }
+      `;
+      const visitor = createAndGenerateVisitor(schema);
+      expect(visitor.models.Post).toBeDefined();
+
+      const postFields = visitor.models.Post.fields;
+      const createdAtField = postFields.find(field => field.name === 'createdAt');
+      expect(createdAtField).not.toBeDefined();
+      const updatedAtField = postFields.find(field => field.name === 'updatedAt');
+      expect(updatedAtField).not.toBeDefined();
+    });
   });
 
   describe('manyToMany testing', () => {

packages/appsync-modelgen-plugin/src/visitors/appsync-visitor.ts

@@ -853,6 +853,10 @@ export class AppSyncModelVisitor<
     if (directive.name !== 'model') {
       return;
     }
+    //when the '{timestamps: null}' is defined in @model, the timestamp fields should not be generated
+    if (directive.arguments && directive.arguments.hasOwnProperty('timestamps') && directive.arguments.timestamps === null) {
+      return;
+    }
     const timestamps = directive.arguments.timestamps;
     const createdAtField: CodeGenField = {
       name: timestamps?.createdAt || DEFAULT_CREATED_TIME,