Unix Timestamps in JavaScript

// Current Unix timestamp (seconds)
const timestamp = Math.floor(Date.now() / 1000);
console.log(timestamp);

// Current timestamp (milliseconds)
const timestampMs = Date.now();
console.log(timestampMs);

// Timestamp to Date
const ts = 1704067200;
const date = new Date(ts * 1000);  // multiply by 1000 for seconds
console.log(date.toISOString());  // '2024-01-01T00:00:00.000Z'

// Date to timestamp
const now = new Date();
const tsNow = Math.floor(now.getTime() / 1000);

// Parse date string to timestamp
const parsed = Date.parse('2025-01-27T12:00:00Z') / 1000;

// Format date
const options = { year: 'numeric', month: 'long', day: 'numeric' };
date.toLocaleDateString('en-US', options);  // 'January 1, 2024'

// Add days
const future = new Date(date);
future.setDate(future.getDate() + 7);

// Difference between dates (in days)
const diff = Math.floor((date2 - date1) / (1000 * 60 * 60 * 24));

// Timezone offset (minutes)
const offset = new Date().getTimezoneOffset();