Typescript：-无法将对象类型值分配给字符串类型变量

此处res ['createdBy'] = createdby; typeof res ['createdBy']是字符串，typeof createdby是对象，我无法分配它，我将使用下面的代码它将正常工作。 res ['updatedBy'] = JSON.stringify（updatedby）;但在这种情况下，它将被分配为字符串，但我需要对象。

fetch('http://localhost:8080/graphql', requestOptions)
            .then((result: any) => result.json())
            .then((output: any) => {
              const usersdata = output.data;
              newresponse = response.map(function (res) {
                const createdby = usersdata['rhatUUID_' + res['createdBy']];
                const updatedby = usersdata['rhatUUID_' + res['updatedBy']];
                res['createdBy'] = createdby;
                res['updatedBy'] = JSON.stringify(updatedby);
                return res;
              });
            })
            .catch((error: any) => console.log('error', error));
          return newresponse;
        })
        .catch((error: any) => console.log('error', error));```