Add removeUndefinedValues support for update operations (#178)

* Initial plan

* Add removeUndefinedValues option and filter undefined in updates

Co-authored-by: snehithv <7270678+snehithv@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: snehithv <7270678+snehithv@users.noreply.github.com>

Author: Copilot

src/DynamoHelper.spec.ts

@@ -0,0 +1,51 @@
+import { DynamoHelper } from './DynamoHelper';
+import { DynamoDBDocumentClient, UpdateCommand } from '@aws-sdk/lib-dynamodb';
+
+describe('DynamoHelper', () => {
+  const tableConfig = {
+    name: 'test-table',
+    indexes: {
+      default: {
+        partitionKeyName: 'pk',
+        sortKeyName: 'sk',
+      },
+    },
+  };
+
+  it('should create DynamoDBDocumentClient with removeUndefinedValues option', () => {
+    const helper = new DynamoHelper(tableConfig, 'us-east-1');
+
+    // Verify that the dbClient is an instance of DynamoDBDocumentClient
+    expect(helper.dbClient).toBeDefined();
+    expect(helper.dbClient).toBeInstanceOf(DynamoDBDocumentClient);
+  });
+
+  it('should handle updates with undefined values correctly', async () => {
+    const helper = new DynamoHelper(tableConfig, 'us-east-1');
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const spy = jest.spyOn(helper.dbClient, 'send').mockResolvedValue({} as any);
+
+    const key = { pk: 'test_pk', sk: 'test_sk' };
+    const item = {
+      name: 'Test',
+      age: 30,
+      undefinedField: undefined,
+      description: 'A test item',
+    };
+
+    await helper.updateItem(key, item, []);
+
+    // Verify that the send method was called
+    expect(spy).toHaveBeenCalled();
+
+    // Verify that the UpdateExpression does not include the undefinedField
+    const command = spy.mock.calls[0][0] as UpdateCommand;
+    expect(command.input.UpdateExpression).toBeDefined();
+    expect(command.input.UpdateExpression).not.toContain('undefinedField');
+    expect(command.input.UpdateExpression).toContain('name');
+    expect(command.input.UpdateExpression).toContain('age');
+    expect(command.input.UpdateExpression).toContain('description');
+
+    spy.mockRestore();
+  });
+});

src/DynamoHelper.ts

@@ -43,7 +43,11 @@ export class DynamoHelper {
       region,
       endpoint,
     });
-    this.dbClient = DynamoDBDocumentClient.from(client);
+    this.dbClient = DynamoDBDocumentClient.from(client, {
+      marshallOptions: {
+        removeUndefinedValues: true,
+      },
+    });
     this.table = table;
   }
 

src/mutation/expressionBuilder.spec.ts

@@ -133,5 +133,30 @@ describe('expressionBuilder', () => {
       expect(result.attrNames).toEqual({});
       expect(result.attrValues).toEqual({});
     });
+
+    it('should remove undefined values from update expression', () => {
+      const result = buildUpdateExpressions({
+        name: 'John',
+        age: 30,
+        undefinedField: undefined,
+        status: 'active',
+      });
+
+      expect(result.expression).toContain('SET ');
+      expect(result.expression).toContain('#key_name = :val_name');
+      expect(result.expression).toContain('#key_age = :val_age');
+      expect(result.expression).toContain('#key_status = :val_status');
+      expect(result.expression).not.toContain('undefinedField');
+      expect(result.attrNames).toEqual({
+        '#key_name': 'name',
+        '#key_age': 'age',
+        '#key_status': 'status',
+      });
+      expect(result.attrValues).toEqual({
+        ':val_name': 'John',
+        ':val_age': 30,
+        ':val_status': 'active',
+      });
+    });
   });
 });

src/mutation/expressionBuilder.ts

@@ -62,9 +62,12 @@ export const buildUpdateExpressions = (item: object): ConditionExpressionReturn
   const expressionNames = {};
 
   Object.keys(item)?.forEach(key => {
-    expressions.push(`#key_${key} = :val_${key}`);
-    expressionNames[`#key_${key}`] = key;
-    expressionValues[`:val_${key}`] = item[key];
+    // Skip undefined values to remove them from update expression
+    if (item[key] !== undefined) {
+      expressions.push(`#key_${key} = :val_${key}`);
+      expressionNames[`#key_${key}`] = key;
+      expressionValues[`:val_${key}`] = item[key];
+    }
   });
 
   return {

tsconfig.build.json

@@ -12,5 +12,5 @@
     "skipLibCheck": true
   },
 
-  "exclude": ["node_modules", "dist"]
+  "exclude": ["node_modules", "dist", "**/*.spec.ts"]
 }