Date Arithmetic in JavaScript

1// Method 1: Add/subtract days
2function addDays(date, days) {
3    const result = new Date(date);
4    result.setDate(result.getDate() + days);
5    return result;
6}
7
8function subtractDays(date, days) {
9    return addDays(date, -days);
10}
11
12const today = new Date();
13console.log('Today:', today);
14console.log('Tomorrow:', addDays(today, 1));
15console.log('Yesterday:', subtractDays(today, 1));
16
17// Method 2: Add/subtract months
18function addMonths(date, months) {
19    const result = new Date(date);
20    result.setMonth(result.getMonth() + months);
21    return result;
22}
23
24console.log('Next month:', addMonths(today, 1));
25console.log('Last month:', addMonths(today, -1));
26
27// Method 3: Add/subtract years
28function addYears(date, years) {
29    const result = new Date(date);
30    result.setFullYear(result.getFullYear() + years);
31    return result;
32}
33
34console.log('Next year:', addYears(today, 1));
35
36// Method 4: Add/subtract hours
37function addHours(date, hours) {
38    const result = new Date(date);
39    result.setHours(result.getHours() + hours);
40    return result;
41}
42
43console.log('In 2 hours:', addHours(today, 2));
44
45// Method 5: Add/subtract minutes
46function addMinutes(date, minutes) {
47    const result = new Date(date);
48    result.setMinutes(result.getMinutes() + minutes);
49    return result;
50}
51
52console.log('In 30 minutes:', addMinutes(today, 30));
53
54// Method 6: Using timestamps
55function addTime(date, milliseconds) {
56    return new Date(date.getTime() + milliseconds);
57}
58
59console.log('Add 1 day (ms):', addTime(today, 24 * 60 * 60 * 1000));
60console.log('Add 1 hour (ms):', addTime(today, 60 * 60 * 1000));
61
62// Method 7: Date difference
63function dateDifference(date1, date2) {
64    const diff = Math.abs(date1 - date2);
65    const days = Math.floor(diff / (1000 * 60 * 60 * 24));
66    const hours = Math.floor((diff % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
67    const minutes = Math.floor((diff % (1000 * 60 * 60)) / (1000 * 60));
68    return { days, hours, minutes };
69}
70
71const date1 = new Date('2024-01-01');
72const date2 = new Date('2024-01-15');
73console.log('Difference:', dateDifference(date1, date2));