Support optional type (e.g. string | undefined, maybeString?: string)

Signed-off-by: moznion <moznion@mail.moznion.net>

Author: moznion

lib/dynamodb_primitive_types.ts

@@ -28,6 +28,15 @@ export function dynamodbPrimitiveTypeFromTypeFlag(flag: ts.TypeFlags | undefined
 }
 
 export function dynamodbPrimitiveTypeFromName(typeName: string | undefined): DynamodbPrimitiveTypes | undefined {
+  if (typeName === undefined) {
+    return undefined;
+  }
+
+  const unionTypes: string[] = typeName.split('|').map(t => t.trim());
+  const isUndefinedType = (t: string): boolean => t === 'undefined';
+  // const isOptionalType = unionTypes.find(isUndefinedType);
+  typeName = unionTypes.filter(t => !isUndefinedType(t)).join('|');
+
   switch (typeName) {
     case 'string':
       return DynamodbPrimitiveTypes.String;

tests/transformer.test.ts

@@ -285,4 +285,30 @@ describe('dynamodb record transform', () => {
     expect(record['tags']).toEqual({ M: { foo: { S: 'bar' }, buz: { S: 'qux' } } });
     expect(Object.keys(record)).toHaveLength(3);
   });
+
+  test('optional', () => {
+    class Clazz {
+      constructor(
+        readonly optionalStr1: string | undefined,
+        readonly optionalStr2: undefined | string,
+        readonly optionalStr3?: string,
+      ) {}
+    }
+
+    {
+      const record: Record<keyof Clazz, AttributeValue> = dynamodbRecord<Clazz>(
+        new Clazz(undefined, undefined, undefined),
+      );
+      expect(record['optionalStr1']).toEqual({ S: undefined });
+      expect(record['optionalStr2']).toEqual({ S: undefined });
+      expect(record['optionalStr3']).toEqual({ S: undefined });
+    }
+
+    {
+      const record: Record<keyof Clazz, AttributeValue> = dynamodbRecord<Clazz>(new Clazz('foo', 'bar', 'buz'));
+      expect(record['optionalStr1']).toEqual({ S: 'foo' });
+      expect(record['optionalStr2']).toEqual({ S: 'bar' });
+      expect(record['optionalStr3']).toEqual({ S: 'buz' });
+    }
+  });
 });