Timezone Conversion in JavaScript

1// Method 1: Get timezone offset
2function getTimezoneOffset() {
3    const offset = new Date().getTimezoneOffset();
4    const hours = Math.floor(Math.abs(offset) / 60);
5    const minutes = Math.abs(offset) % 60;
6    const sign = offset > 0 ? '-' : '+';
7    return `${sign}${String(hours).padStart(2, '0')}:${String(minutes).padStart(2, '0')}`;
8}
9
10console.log('Timezone offset:', getTimezoneOffset());
11
12// Method 2: Convert to UTC
13function toUTC(date) {
14    return new Date(date.toUTCString());
15}
16
17const localDate = new Date();
18console.log('Local:', localDate);
19console.log('UTC:', toUTC(localDate));
20
21// Method 3: Convert to specific timezone (using Intl)
22function toTimezone(date, timezone) {
23    return new Date(date.toLocaleString('en-US', { timeZone: timezone }));
24}
25
26const date = new Date();
27console.log('New York:', toTimezone(date, 'America/New_York'));
28console.log('Tokyo:', toTimezone(date, 'Asia/Tokyo'));
29console.log('London:', toTimezone(date, 'Europe/London'));
30
31// Method 4: Format with timezone
32function formatWithTimezone(date, timezone) {
33    return new Intl.DateTimeFormat('en-US', {
34        timeZone: timezone,
35        year: 'numeric',
36        month: '2-digit',
37        day: '2-digit',
38        hour: '2-digit',
39        minute: '2-digit',
40        second: '2-digit',
41        hour12: false
42    }).format(date);
43}
44
45console.log('NY formatted:', formatWithTimezone(date, 'America/New_York'));
46
47// Method 5: List available timezones
48function getTimezones() {
49    return Intl.supportedValuesOf('timeZone');
50}
51
52console.log('Available timezones:', getTimezones().slice(0, 5));
53
54// Method 6: Convert between timezones
55function convertTimezone(date, fromTZ, toTZ) {
56    const fromDate = new Date(date.toLocaleString('en-US', { timeZone: fromTZ }));
57    const toDate = new Date(date.toLocaleString('en-US', { timeZone: toTZ }));
58    return toDate;
59}
60
61const nyDate = new Date('2024-01-15T12:00:00');
62const tokyoDate = convertTimezone(nyDate, 'America/New_York', 'Asia/Tokyo');
63console.log('NY to Tokyo:', tokyoDate);