1.0.36

src/lib/utils/date-format.ts

@@ -0,0 +1,84 @@
+/**
+ * Pure date/time formatting helpers — no SvelteKit / store imports.
+ *
+ * settings.ts wraps these with cached preferences and a reactive subscription;
+ * keeping the implementation here lets the formatters be unit-tested without
+ * dragging in $app/environment or svelte/store.
+ */
+
+export type TimeFormat = '12h' | '24h';
+export type DateFormat = 'MM/DD/YYYY' | 'DD/MM/YYYY' | 'YYYY-MM-DD' | 'DD.MM.YYYY';
+
+export interface DateTimeFormatters {
+	date: Intl.DateTimeFormat;
+	time: Intl.DateTimeFormat;
+}
+
+// Intl.DateTimeFormat construction is expensive; the caller caches one pair per
+// timezone and rebuilds only when the timezone setting changes.
+export function buildFormatters(timeZone: string | undefined): DateTimeFormatters {
+	const tz = timeZone || undefined;
+	return {
+		date: new Intl.DateTimeFormat('en-GB', {
+			timeZone: tz,
+			year: 'numeric',
+			month: '2-digit',
+			day: '2-digit'
+		}),
+		time: new Intl.DateTimeFormat('en-GB', {
+			timeZone: tz,
+			hour: '2-digit',
+			minute: '2-digit',
+			second: '2-digit',
+			hour12: false
+		})
+	};
+}
+
+function pickPart(parts: Intl.DateTimeFormatPart[], type: Intl.DateTimeFormatPartTypes): string {
+	return parts.find((p) => p.type === type)?.value ?? '';
+}
+
+export function formatDatePartWith(d: Date, dateFormatter: Intl.DateTimeFormat, dateFormat: DateFormat): string {
+	const parts = dateFormatter.formatToParts(d);
+	const day = pickPart(parts, 'day');
+	const month = pickPart(parts, 'month');
+	const year = pickPart(parts, 'year');
+
+	switch (dateFormat) {
+		case 'MM/DD/YYYY':
+			return `${month}/${day}/${year}`;
+		case 'DD/MM/YYYY':
+			return `${day}/${month}/${year}`;
+		case 'YYYY-MM-DD':
+			return `${year}-${month}-${day}`;
+		case 'DD.MM.YYYY':
+		default:
+			return `${day}.${month}.${year}`;
+	}
+}
+
+export function formatTimePartWith(
+	d: Date,
+	timeFormatter: Intl.DateTimeFormat,
+	timeFormat: TimeFormat,
+	includeSeconds = false
+): string {
+	const parts = timeFormatter.formatToParts(d);
+	const hours = parseInt(pickPart(parts, 'hour'), 10);
+	const minutes = pickPart(parts, 'minute');
+	const seconds = pickPart(parts, 'second');
+
+	if (timeFormat === '12h') {
+		const hour12 = hours === 0 ? 12 : hours > 12 ? hours - 12 : hours;
+		const ampm = hours >= 12 ? 'PM' : 'AM';
+		return includeSeconds
+			? `${hour12}:${minutes}:${seconds} ${ampm}`
+			: `${hour12}:${minutes} ${ampm}`;
+	} else {
+		const hour24 = hours.toString().padStart(2, '0');
+		return includeSeconds
+			? `${hour24}:${minutes}:${seconds}`
+			: `${hour24}:${minutes}`;
+	}
+}