Initial commit: Analytics frontend implementation

lib/utils/format.ts

@@ -0,0 +1,44 @@
+/**
+ * Format numbers with commas
+ */
+export function formatNumber(num: number): string {
+  return new Intl.NumberFormat('en-US').format(num)
+}
+
+/**
+ * Format date to YYYY-MM-DD
+ */
+export function formatDate(date: Date): string {
+  return date.toISOString().split('T')[0]
+}
+
+/**
+ * Get date range for last N days
+ */
+export function getDateRange(days: number): { start: string; end: string } {
+  const end = new Date()
+  const start = new Date()
+  start.setDate(start.getDate() - days)
+  return {
+    start: formatDate(start),
+    end: formatDate(end),
+  }
+}
+
+/**
+ * Format relative time (e.g., "2 hours ago")
+ */
+export function formatRelativeTime(date: string | Date): string {
+  const d = typeof date === 'string' ? new Date(date) : date
+  const now = new Date()
+  const diff = now.getTime() - d.getTime()
+  const seconds = Math.floor(diff / 1000)
+  const minutes = Math.floor(seconds / 60)
+  const hours = Math.floor(minutes / 60)
+  const days = Math.floor(hours / 24)
+
+  if (days > 0) return `${days} day${days > 1 ? 's' : ''} ago`
+  if (hours > 0) return `${hours} hour${hours > 1 ? 's' : ''} ago`
+  if (minutes > 0) return `${minutes} minute${minutes > 1 ? 's' : ''} ago`
+  return 'Just now'
+}