Update AddArtist.ts

src/pages/them-nghe-sy/AddArtist.ts

@@ -816,7 +816,7 @@ export default defineComponent({
             artistCode: artistCode.value,
             artistName: artistName.value,
             // eslint-disable-next-line @typescript-eslint/restrict-plus-operands
-            birthday: birthday.value === null ? '' :  birthday.value + ' 00:00:00',
+            birthday: birthday.value === null ? null :  birthday.value + ' 00:00:00',
             sex: sex.value,
             provinceDto: address.value,
             address: null,