What is the Date object in JavaScript?

The built-in Date object in JavaScript handles dates, times, and calendar calculations. It internally stores time as an integer representing the number of milliseconds elapsed since the Unix Epoch (Midnight January 1, 1970, UTC).

### Basic Usage:

// Current timestamp
const now = new Date();

// Specific date (Year, MonthIndex 0-11, Day, Hour, Min, Sec)
const launch = new Date(2026, 8, 20); // Note: September is month index 8!

// ISO 8601 String
const utcDate = new Date("2026-09-20T12:00:00Z");

### Common Gotchas with Date:

1. Zero-Indexed Months: date.getMonth() returns 0 for January and 11 for December.
2. Local Time vs UTC: Standard getters (getHours(), getDate()) use the user's local operating system timezone, which can cause subtle date shift bugs for users across different timezones.
3. Modern Alternative (Temporal API):

The upcoming TC39 Temporal specification addresses Date limitations by providing immutable, timezone-aware objects (Temporal.Now.plainDateISO()). For current production code, libraries like date-fns or Day.js are preferred.