first commit. working

utils/csvExport.ts

@@ -0,0 +1,13 @@
+export function exportToCsv(filename: string, rows: any[]) {
+  if (!rows.length) return;
+  const keys = Object.keys(rows[0]);
+  const csv = keys.join(',') + '\\n' +
+    rows.map(r => keys.map(k => JSON.stringify(r[k] || '')).join(',')).join('\\n');
+  const blob = new Blob([csv], { type: 'text/csv' });
+  const link = document.createElement('a');
+  link.href = URL.createObjectURL(blob);
+  link.download = filename;
+  document.body.appendChild(link);
+  link.click();
+  link.remove();
+}

utils/db.ts

@@ -0,0 +1,24 @@
+import Dexie from 'dexie';
+
+export interface Teacher { id: string; name: string }
+export interface AttendanceRecord {
+  id: string;
+  teacherId: string;
+  timestamp: number;
+  type: 'in' | 'out';
+}
+
+export class AppDB extends Dexie {
+  teachers!: Dexie.Table<Teacher, string>;
+  records!: Dexie.Table<AttendanceRecord, string>;
+
+  constructor() {
+    super('AttendanceDB');
+    this.version(1).stores({
+      teachers: 'id, name',
+      records: 'id, teacherId, timestamp, type',
+    });
+  }
+}
+
+export const db = new AppDB();