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JavaScript Date objects are essential for handling dates, times, and timestamps in web development. Understanding their creation, manipulation, formatting, and reference behavior is crucial for reliable applications.
const now = new Date();
console.log(now); // Thu Oct 09 2025 18:06:00 GMT+0530 (India Standard Time)
const now = new Date();
console.log(now);
ISO 8601 format is recommended for consistency:
const date = new Date('2025-10-09'); // Local time
console.log(date); // 2025-10-09T00:00:00.000Z
const date = new Date(2025, 9, 9, 18, 6, 0); // Month is 0-based
console.log(date); // 2025-10-09T18:06:00.000Z
const date = new Date(1760148960000);
console.log(date); // Wed Oct 08 2025 18:19:22
| Format Type | Syntax / Example | Notes |
|---|---|---|
| ISO | "2025-10-08" | Standard, cross-browser reliable |
| ISO with Time | "2025-10-08T18:30:00" | Local time |
| ISO UTC | "2025-10-08T18:30:00Z" | UTC, ideal for APIs |
| Short (US) | "10/08/2025" | Browser-dependent |
| Long | "October 8, 2025" | Human-readable |
| Milliseconds | 1760148960000 | Calculations & storage |
| Method | Example Output | Description |
|---|---|---|
toString() | Thu Oct 09 2025 18:06:00 GMT+0530 | Default local string |
toDateString() | Thu Oct 09 2025 | Human-readable date |
toTimeString() | 18:06:00 GMT+0530 | Time only |
toUTCString() | Thu, 09 Oct 2025 12:36:00 GMT | UTC time |
toISOString() | 2025-10-09T12:36:00.000Z | ISO 8601 UTC |
toLocaleString() | 10/9/2025, 6:06:00 PM | Localized date & time |
toLocaleDateString() | 10/9/2025 | Localized date |
toLocaleTimeString() | 6:06:00 PM | Localized time |
Retrieve parts of a date object. Local time vs UTC variants exist.
| Method | Returns | Example |
|---|---|---|
getFullYear() | Year (4 digits) | 2025 |
getMonth() | Month (0–11) | 9 (October) |
getDate() | Day of month (1–31) | 9 |
getDay() | Day of week (0–6) | 4 (Thursday) |
getHours() | Hours (0–23) | 18 |
getMinutes() | Minutes (0–59) | 6 |
getSeconds() | Seconds (0–59) | 0 |
getMilliseconds() | Milliseconds (0–999) | 0 |
getTime() | Milliseconds since epoch | 1760148960000 |
getTimezoneOffset() | Minutes difference from UTC | -330 |
Modify an existing Date object in place.
| Method | Parameters | Example |
|---|---|---|
setFullYear(year[, month, date]) | 2026, 0, 15 | Sets year, optional month/day |
setMonth(month[, date]) | 0–11, 1–31 | date.setMonth(0) → January |
setDate(date) | 1–31 | date.setDate(15) |
setHours(hours[, min, sec, ms]) | 0–23 | date.setHours(14,30) |
setMinutes(min[, sec, ms]) | 0–59 | date.setMinutes(45) |
setSeconds(sec[, ms]) | 0–59 | date.setSeconds(30) |
setMilliseconds(ms) | 0–999 | date.setMilliseconds(500) |
setTime(ms) | Milliseconds since epoch | date.setTime(1760148960000) |
.getTime():const date1 = new Date('2025-10-09T18:06:00+05:30');
const date2 = new Date(date1.getTime()); // Independent copy
date2.setDate(20);
console.log(date1.toLocaleString()); // 10/9/2025, 6:06 PM
console.log(date2.toLocaleString()); // 10/20/2025, 6:06 PM
| Method | Description | Example |
|---|---|---|
Date.now() | Current timestamp | 1760148960000 |
Date.parse(string) | Parse string to ms | Date.parse('2025-10-09') → 1760073600000 |
Date.UTC(year, month, …) | Milliseconds for UTC date | Date.UTC(2025, 9, 9) |
Create, Get, Set, Format Dates
const date = new Date('2025-10-09T18:06:00+05:30');
// Get components
console.log(date.getFullYear()); // 2025
console.log(date.getMonth()); // 9
console.log(date.getDate()); // 9
// Set components
date.setFullYear(2026);
date.setMonth(0); // January
date.setDate(15);
date.setHours(14, 30);
console.log(date.toLocaleString('en-US')); // 1/15/2026, 2:30:00 PM
// UTC example
console.log(date.getUTCHours()); // 9
date.setUTCHours(12);
console.log(date.toISOString()); // 2026-01-15T12:00:00.000Z
Calculate Time Difference
const start = new Date('2025-10-09T18:06:00+05:30');
const end = new Date('2025-10-10T18:06:00+05:30');
const diffDays = (end - start) / (1000 * 60 * 60 * 24);
console.log(diffDays); // 1