jsonPayload = JSON.stringify({ "name" : customElementString.name, "shortName" : customElementString.shortName, "aggregationType": customElementString.aggregationType, "domainType": customElementString.domainType, "valueType" : customElementString.valueType, "code" : updateArray[i].value, "displayName": customElementString.displayName, "displayShortName": customElementString.displayShortName, "displayFormName" : customElementString.displayFormName, "formName" : customElementString.formName, "url" : customElementString.url, "optionSet": { "id": customElementString.optionSet.id }, "categoryCombo": { "id": customElementString.categoryCombo.id } }); Another way: let customElementString = response.data; let jsonPayload = JSON.stringify({ ...customElementString code: updateArray[i].value });