implemented bill deletion + var rename

app/lib/db-types.ts

@@ -8,42 +8,20 @@ export interface BillAttachment {
     fileContentsBase64: string;
 };
 
-/** Bill basic data */
-export interface LocationBase {
+/** bill object in the form returned by MongoDB */
+export interface BillingLocation {
+    _id: string;
     name: string;
     /** the value is encoded as yyyymm (i.e. 202301) */
     yearMonth: number;
+    bills: Bill[];
 };
 
-
-/** bill object in the form returned by MongoDB */
-export interface MongoLocation {
-    _id: ObjectId;
-    bills: MongoBill[];
-};
-
-/** plain-object Location version */
-export interface PlainLocation {
-    id: string;
-    bills: PlainBill[];
-};
-
-
 /** Bill basic data */
-export interface BillBase {
+export interface Bill {
+    _id: string;
     name: string;
     paid: boolean;
     attachment?: BillAttachment|null;
     notes?: string|null;
-};
-
-/** bill object in the form returned by MongoDB */
-export interface MongoBill extends BillBase {
-    _id: ObjectId;
-};
-
-
-/** plain-object bill version */
-export interface PlainBill extends BillBase {
-    id: string;
-};
+};