/**
* Date Object Example in TypeScript
* ---------------------------------
* Demonstrates:
* - Creating Date objects
* - Reading date parts
* - Formatting dates
* - Adding days to a date
* - Calculating date differences
* - Using TypeScript type annotations
*/
"use strict";
/**
* Formats a Date object as YYYY-MM-DD HH:mm:ss
*
* @param date Date to format
* @returns Formatted date string
*/
function formatDate(date: Date): string {
if (isNaN(date.getTime())) {
throw new Error("Invalid Date.");
}
const year: number = date.getFullYear();
const month: string = String(date.getMonth() + 1).padStart(2, "0");
const day: string = String(date.getDate()).padStart(2, "0");
const hours: string = String(date.getHours()).padStart(2, "0");
const minutes: string = String(date.getMinutes()).padStart(2, "0");
const seconds: string = String(date.getSeconds()).padStart(2, "0");
return `${year}-${month}-${day} ${hours}:${minutes}:${seconds}`;
}
/**
* Adds a specified number of days to a date.
*
* @param date Original date
* @param days Number of days to add
* @returns New Date instance
*/
function addDays(date: Date, days: number): Date {
const result: Date = new Date(date);
result.setDate(result.getDate() + days);
return result;
}
/**
* Calculates the number of days between two dates.
*
* @param startDate Starting date
* @param endDate Ending date
* @returns Number of days
*/
function getDaysBetween(startDate: Date, endDate: Date): number {
const millisecondsPerDay: number = 1000 * 60 * 60 * 24;
const differenceInMs: number =
endDate.getTime() - startDate.getTime();
return differenceInMs / millisecondsPerDay;
}
// ------------------------------------------------------------------
// Usage Examples
// ------------------------------------------------------------------
console.log("=== Current Date and Time ===");
// Current date/time
const now: Date = new Date();
console.log(now);
console.log(formatDate(now));
console.log("\n=== Creating Specific Dates ===");
// Create a date from an ISO string
const projectStartDate: Date = new Date("2026-01-15T09:00:00");
console.log(formatDate(projectStartDate));
console.log("\n=== Reading Date Parts ===");
const year: number = projectStartDate.getFullYear();
const month: number = projectStartDate.getMonth() + 1; // Months are 0-based
const day: number = projectStartDate.getDate();
console.log(`Year: ${year}`);
console.log(`Month: ${month}`);
console.log(`Day: ${day}`);
console.log("\n=== Adding Days ===");
const deadline: Date = addDays(projectStartDate, 30);
console.log("Start Date :", formatDate(projectStartDate));
console.log("Deadline :", formatDate(deadline));
console.log("\n=== Difference Between Dates ===");
const daysBetween: number = getDaysBetween(
projectStartDate,
deadline
);
console.log(`Difference: ${daysBetween} days`);
console.log("\n=== ISO Format ===");
// Best format for APIs and databases
const isoDate: string = now.toISOString();
console.log(isoDate);
console.log("\n=== Localized Format ===");
// Best format for display to users
const localizedDate: string = now.toLocaleString("en-US", {
dateStyle: "full",
timeStyle: "long"
});
console.log(localizedDate);
/*
run:
=== Current Date and Time ===
2026-10-16T15:18:02.485Z
2026-10-16 15:18:02
=== Creating Specific Dates ===
2026-01-15 09:00:00
=== Reading Date Parts ===
Year: 2026
Month: 1
Day: 15
=== Adding Days ===
Start Date : 2026-01-15 09:00:00
Deadline : 2026-02-14 09:00:00
=== Difference Between Dates ===
Difference: 30 days
=== ISO Format ===
2026-10-16T15:18:02.485Z
=== Localized Format ===
Friday, October 16, 2026 at 3:18:02 PM UTC
*/
