Compare Dates in JavaScript

1// Method 1: Compare timestamps
2function compareDates(date1, date2) {
3    if (date1.getTime() === date2.getTime()) {
4        return 0; // Equal
5    } else if (date1.getTime() > date2.getTime()) {
6        return 1; // date1 is later
7    } else {
8        return -1; // date1 is earlier
9    }
10}
11
12const date1 = new Date('2024-01-15');
13const date2 = new Date('2024-01-20');
14console.log('Compare:', compareDates(date1, date2));
15
16// Method 2: Simple comparisons
17console.log('date1 > date2:', date1 > date2);
18console.log('date1 < date2:', date1 < date2);
19console.log('date1 === date2:', date1.getTime() === date2.getTime());
20
21// Method 3: Check if date is in range
22function isDateInRange(date, startDate, endDate) {
23    return date >= startDate && date <= endDate;
24}
25
26const checkDate = new Date('2024-01-18');
27const start = new Date('2024-01-15');
28const end = new Date('2024-01-20');
29console.log('In range:', isDateInRange(checkDate, start, end));
30
31// Method 4: Check if date is today
32function isToday(date) {
33    const today = new Date();
34    return date.getDate() === today.getDate() &&
35           date.getMonth() === today.getMonth() &&
36           date.getFullYear() === today.getFullYear();
37}
38
39console.log('Is today:', isToday(new Date()));
40
41// Method 5: Check if date is past/future
42function isPast(date) {
43    return date < new Date();
44}
45
46function isFuture(date) {
47    return date > new Date();
48}
49
50console.log('Is past:', isPast(new Date('2020-01-01')));
51console.log('Is future:', isFuture(new Date('2025-01-01')));
52
53// Method 6: Compare dates (ignore time)
54function compareDatesOnly(date1, date2) {
55    const d1 = new Date(date1.getFullYear(), date1.getMonth(), date1.getDate());
56    const d2 = new Date(date2.getFullYear(), date2.getMonth(), date2.getDate());
57    return d1.getTime() - d2.getTime();
58}
59
60const dateWithTime = new Date('2024-01-15T15:30:00');
61const dateWithoutTime = new Date('2024-01-15T00:00:00');
62console.log('Same date (ignore time):', compareDatesOnly(dateWithTime, dateWithoutTime) === 0);