implented adding year-month

app/page.tsx

@@ -3,14 +3,18 @@ import { MonthTitle } from './ui/MonthTitle';
 import { AddMonthButton } from './ui/AddMonthButton';
 import { AddLocationButton } from './ui/AddLocationButton';
 import clientPromise from './lib/mongodb';
-import { Location } from './lib/db-types';
+import { BillingLocation } from './lib/db-types';
+
+const calcNextYearMonth = (yearMonth: number) => {
+  return(yearMonth % 100 === 12 ? yearMonth + 89 : yearMonth + 1);
+}
 
 export const Page = async () => {
 
  const client = await clientPromise;
  const db = client.db("rezije");
 
- const locations = await db.collection<Location>("lokacije")
+ const locations = await db.collection<BillingLocation>("lokacije")
     .find({})
     .sort({ yearMonth: -1 }) // sort by yearMonth descending
     .limit(20)
@@ -18,7 +22,7 @@ export const Page = async () => {
 
  return (
     <main className="flex min-h-screen flex-col p-6 bg-base-300">
-        <AddMonthButton />
+        <AddMonthButton yearMonth={calcNextYearMonth(locations[0].yearMonth)} />
         {
           locations.map((location, ix, array) => {