Date Validation in JavaScript

1// Method 1: Check if valid date
2function isValidDate(date) {
3    return date instanceof Date && !isNaN(date.getTime());
4}
5
6console.log('Valid:', isValidDate(new Date()));
7console.log('Invalid:', isValidDate(new Date('invalid')));
8
9// Method 2: Validate date string
10function isValidDateString(dateString) {
11    const date = new Date(dateString);
12    return isValidDate(date) && dateString !== 'Invalid Date';
13}
14
15console.log('Valid string:', isValidDateString('2024-01-15'));
16console.log('Invalid string:', isValidDateString('not-a-date'));
17
18// Method 3: Validate date format
19function isValidDateFormat(dateString, format = 'YYYY-MM-DD') {
20    const patterns = {
21        'YYYY-MM-DD': /^\d{4}-\d{2}-\d{2}$/,
22        'DD/MM/YYYY': /^\d{2}\/\d{2}\/\d{4}$/,
23        'MM/DD/YYYY': /^\d{2}\/\d{2}\/\d{4}$/
24    };
25    
26    if (!patterns[format].test(dateString)) {
27        return false;
28    }
29    
30    const date = new Date(dateString);
31    return isValidDate(date);
32}
33
34console.log('Valid format:', isValidDateFormat('2024-01-15', 'YYYY-MM-DD'));
35
36// Method 4: Validate date range
37function isDateInRange(date, minDate, maxDate) {
38    if (!isValidDate(date)) return false;
39    return date >= minDate && date <= maxDate;
40}
41
42const checkDate = new Date('2024-01-15');
43const min = new Date('2024-01-01');
44const max = new Date('2024-12-31');
45console.log('In range:', isDateInRange(checkDate, min, max));
46
47// Method 5: Validate future date
48function isFutureDate(date) {
49    if (!isValidDate(date)) return false;
50    return date > new Date();
51}
52
53console.log('Future date:', isFutureDate(new Date('2025-01-01')));
54
55// Method 6: Validate past date
56function isPastDate(date) {
57    if (!isValidDate(date)) return false;
58    return date < new Date();
59}
60
61console.log('Past date:', isPastDate(new Date('2020-01-01')));
62
63// Method 7: Validate date components
64function validateDateComponents(year, month, day) {
65    if (year < 1900 || year > 2100) return false;
66    if (month < 1 || month > 12) return false;
67    if (day < 1 || day > 31) return false;
68    
69    const date = new Date(year, month - 1, day);
70    return date.getFullYear() === year &&
71           date.getMonth() === month - 1 &&
72           date.getDate() === day;
73}
74
75console.log('Valid components:', validateDateComponents(2024, 1, 15));
76console.log('Invalid components:', validateDateComponents(2024, 2, 30)); // Feb 30 doesn't exist