time

name	time
description	Get current time, date, and timezone information without external APIs. Use when you need to display the current time, calculate time differences, or work with dates and times.

Purpose

This skill provides methods to get the current time, date, and timezone information using built-in system capabilities without requiring external APIs or services.

When to Use

• Displaying current time/date to users
• Calculating time differences
• Working with timezones
• Formatting dates and times
• Scheduling and time-based operations
• Logging timestamps

Getting Current Time

JavaScript (Node.js/Browser)

// Current date and time
const now = new Date();
console.log(now); // 2025-04-30T09:36:00.000Z

// Format as string
console.log(now.toString()); // Wed Apr 30 2025 09:36:00 GMT+0000
console.log(now.toISOString()); // 2025-04-30T09:36:00.000Z
console.log(now.toLocaleString()); // 4/30/2025, 9:36:00 AM

// Get specific components
console.log(now.getFullYear()); // 2025
console.log(now.getMonth()); // 3 (0-indexed: 0-11)
console.log(now.getDate()); // 30
console.log(now.getHours()); // 9
console.log(now.getMinutes()); // 36
console.log(now.getSeconds()); // 0
console.log(now.getMilliseconds()); // 0

// Get day of week (0 = Sunday, 6 = Saturday)
console.log(now.getDay()); // 3 (Wednesday)

Python

from datetime import datetime
import pytz

# Current date and time (local)
now = datetime.now()
print(now)  # 2025-04-30 09:36:00.123456

# Format as string
print(now.strftime("%Y-%m-%d %H:%M:%S"))  # 2025-04-30 09:36:00
print(now.isoformat())  # 2025-04-30T09:36:00.123456

# Get specific components
print(now.year)   # 2025
print(now.month)  # 4
print(now.day)    # 30
print(now.hour)   # 9
print(now.minute) # 36
print(now.second) # 0

# Get day of week (0 = Monday, 6 = Sunday)
print(now.weekday())  # 2 (Wednesday)

Bash/Shell

# Current date and time
date
# Wed Apr 30 09:36:00 UTC 2025

# Custom format
date +"%Y-%m-%d %H:%M:%S"
# 2025-04-30 09:36:00

# Unix timestamp
date +%s
# 1714474560

# UTC time
date -u
# Wed Apr 30 09:36:00 UTC 2025

Timezones

JavaScript

// Get timezone offset (in minutes)
const offset = new Date().getTimezoneOffset();
console.log(offset); // -240 for UTC-4 (Eastern Daylight Time)

// Get timezone name
const timezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
console.log(timezone); // "America/New_York"

// Get time in specific timezone
const options = { timeZone: 'America/New_York' };
const nyTime = new Date().toLocaleString('en-US', options);
console.log(nyTime);

Python

from datetime import datetime
import pytz

# Get local timezone
local_tz = datetime.now().astimezone().tzinfo
print(local_tz)  # tzinfo object

# Get time in specific timezone
ny_tz = pytz.timezone('America/New_York')
ny_time = datetime.now(ny_tz)
print(ny_time.strftime("%Y-%m-%d %H:%M:%S %Z"))

# List all timezones
import pytz
print(pytz.all_timezones[:10])  # First 10 timezones

Time Calculations

JavaScript

// Add time
const now = new Date();
const tomorrow = new Date(now);
tomorrow.setDate(tomorrow.getDate() + 1);

const nextWeek = new Date(now);
nextWeek.setDate(nextWeek.getDate() + 7);

const nextHour = new Date(now);
nextHour.setHours(nextHour.getHours() + 1);

// Subtract time
const yesterday = new Date(now);
yesterday.setDate(yesterday.getDate() - 1);

// Time difference
const date1 = new Date('2025-04-30');
const date2 = new Date('2025-05-01');
const diff = date2 - date1; // in milliseconds
const diffDays = diff / (1000 * 60 * 60 * 24);
console.log(diffDays); // 1

// Unix timestamp
const timestamp = Math.floor(Date.now() / 1000);
console.log(timestamp); // 1714474560

// From timestamp
const fromTimestamp = new Date(timestamp * 1000);
console.log(fromTimestamp);

Python

from datetime import datetime, timedelta

# Add time
now = datetime.now()
tomorrow = now + timedelta(days=1)
next_week = now + timedelta(weeks=1)
next_hour = now + timedelta(hours=1)

# Subtract time
yesterday = now - timedelta(days=1)

# Time difference
date1 = datetime(2025, 4, 30)
date2 = datetime(2025, 5, 1)
diff = date2 - date1
print(diff.days)  # 1

# Unix timestamp
timestamp = int(now.timestamp())
print(timestamp)  # 1714474560

# From timestamp
from_timestamp = datetime.fromtimestamp(timestamp)
print(from_timestamp)

Formatting

JavaScript

const now = new Date();

// Common formats
console.log(now.toDateString()); // "Wed Apr 30 2025"
console.log(now.toTimeString()); // "09:36:00 GMT+0000"
console.log(now.toLocaleDateString()); // "4/30/2025"
console.log(now.toLocaleTimeString()); // "9:36:00 AM"

// Custom format using Intl
const formatter = new Intl.DateTimeFormat('en-US', {
  year: 'numeric',
  month: 'long',
  day: 'numeric',
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
  timeZoneName: 'short'
});
console.log(formatter.format(now));
// "April 30, 2025 at 09:36:00 AM GMT"

// Custom format string
const formatted = now.getFullYear() + '-' + 
  String(now.getMonth() + 1).padStart(2, '0') + '-' + 
  String(now.getDate()).padStart(2, '0');
console.log(formatted); // "2025-04-30"

Python

from datetime import datetime

now = datetime.now()

# Common formats
print(now.strftime("%Y-%m-%d"))  # 2025-04-30
print(now.strftime("%H:%M:%S"))  # 09:36:00
print(now.strftime("%A, %B %d, %Y"))  # Wednesday, April 30, 2025
print(now.strftime("%I:%M %p"))  # 09:36 AM

# Format codes
# %Y - Year (4 digits)
# %m - Month (01-12)
# %d - Day (01-31)
# %H - Hour (00-23, 24-hour)
# %I - Hour (01-12, 12-hour)
# %M - Minute (00-59)
# %S - Second (00-59)
# %p - AM/PM
# %A - Full weekday name
# %B - Full month name

Common Use Cases

Display Current Time

function getCurrentTime() {
  const now = new Date();
  return now.toLocaleTimeString();
}

Display Current Date

function getCurrentDate() {
  const now = new Date();
  return now.toLocaleDateString();
}

Calculate Age

function calculateAge(birthDate) {
  const birth = new Date(birthDate);
  const now = new Date();
  let age = now.getFullYear() - birth.getFullYear();
  const monthDiff = now.getMonth() - birth.getMonth();
  if (monthDiff < 0 || (monthDiff === 0 && now.getDate() < birth.getDate())) {
    age--;
  }
  return age;
}

Check if Date is in Past

function isPast(date) {
  const checkDate = new Date(date);
  const now = new Date();
  return checkDate < now;
}

Get Start of Day

function getStartOfDay(date) {
  const d = new Date(date);
  d.setHours(0, 0, 0, 0);
  return d;
}

Get End of Day

function getEndOfDay(date) {
  const d = new Date(date);
  d.setHours(23, 59, 59, 999);
  return d;
}

Best Practices

• Always use UTC for storage and calculations
• Use local timezones only for display
• Handle timezone conversions explicitly
• Use ISO 8601 format for data exchange
• Be aware of daylight saving time changes
• Use libraries like moment.js or date-fns for complex operations (JavaScript)
• Use pytz or zoneinfo for Python timezone handling
• Test timezone-related code with different timezones
• Consider leap years and other calendar edge cases

Common Gotchas

Month Indexing

JavaScript months are 0-indexed (0 = January, 11 = December):

const date = new Date(2025, 3, 30); // April 30, 2025 (not March)

Timezone Offsets

JavaScript getTimezoneOffset() returns minutes with opposite sign:

const offset = new Date().getTimezoneOffset(); // -240 for UTC+4

Date Parsing

Avoid parsing date strings with Date constructor (browser-dependent):

// Bad
const date = new Date('2025-04-30'); // May be interpreted as UTC or local

// Good
const date = new Date('2025-04-30T00:00:00'); // Explicit format

Leap Years

February 29 only exists in leap years:

const date = new Date(2025, 1, 29); // March 1, 2025 (2025 not a leap year)

Scripts

get-time.js

#!/usr/bin/env node

const now = new Date();

console.log('Current Time:');
console.log('─'.repeat(40));
console.log('ISO:', now.toISOString());
console.log('Local:', now.toLocaleString());
console.log('UTC:', now.toUTCString());
console.log('Unix:', Math.floor(now.getTime() / 1000));
console.log('Timezone:', Intl.DateTimeFormat().resolvedOptions().timeZone);
console.log('─'.repeat(40));

get-time.py

#!/usr/bin/env python3

from datetime import datetime
import pytz

now = datetime.now()
utc_now = datetime.utcnow()

print('Current Time:')
print('─' * 40)
print('ISO:', now.isoformat())
print('Local:', now.strftime('%Y-%m-%d %H:%M:%S'))
print('UTC:', utc_now.strftime('%Y-%m-%d %H:%M:%S'))
print('Unix:', int(now.timestamp()))
print('Timezone:', datetime.now().astimezone().tzinfo)
print('─' * 40)