You need to specify the field attribute in your columns that match with the response data object, for example:
request(invoicesDataUrl, {
handleAs: "json"
}).then(function (response) {
var store = new Memory({ data: response });
var grid = new OnDemandGrid({
region: "center",
store: store,
columns: {
invoice_id: { label: "FID", field: "invoice_id" },
user_id: { label: "UID", field: "user_id" },
invoice_no: { label: "Číslo", field: "invoice_no" },
user_fullname: { label: "Plátce", field: "user_fullname" },
created_formatted: { label: "Vystavena", field: "created_formatted" },
payment_date_formatted: { label: "Splatnost", field: "payment_date_formatted" },
payment_total: { label: "Částka", field: "payment_total" }
}
}, "invoicesGridTab2");
grid.startup();
});
I do not know if those field names are correct, but I assume you would. :)