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Generate Random Dates in JavaScript

Complete code tutorial with examples and best practices

PHP

JavaScript

[ Code Example - Quick Summary ]

Language: JavaScript

What: Generate random dates in JavaScript for frontend and Node.js applications. Covers Date objects, date ranges, formatting with moment.js and date-fns, and timezone handling.

Try it: Use our interactive Dates generator or integrate this code into your JavaScript application.

Generate random dates in JavaScript for frontend and Node.js applications. Covers Date objects, date ranges, formatting with moment.js and date-fns, and timezone handling. Looking for other languages? Check our code examples in PHP , Python , Java , C# , C++ , Ruby and Go or use our interactive web generator.

JavaScript Code Example

// Generate random date between two dates
function randomDate(startDate, endDate) {
    const start = new Date(startDate).getTime();
    const end = new Date(endDate).getTime();
    const randomTimestamp = Math.floor(Math.random() * (end - start + 1)) + start;
    return new Date(randomTimestamp);
}

// Generate random date as ISO string
function randomDateISO(startDate, endDate) {
    return randomDate(startDate, endDate).toISOString().split("T")[0];
}

// Generate random past date (within last N days)
function randomPastDate(daysAgo = 365) {
    const now = new Date();
    const past = new Date(now.getTime() - Math.random() * daysAgo * 86400000);
    return past;
}

// Generate random future date (within next N days)
function randomFutureDate(daysAhead = 365) {
    const now = new Date();
    const future = new Date(now.getTime() + Math.random() * daysAhead * 86400000);
    return future;
}

// Generate random birthday (18-80 years ago)
function randomBirthday() {
    const now = new Date();
    const minAge = 18;
    const maxAge = 80;
    const minDate = new Date(now.getFullYear() - maxAge, now.getMonth(), now.getDate());
    const maxDate = new Date(now.getFullYear() - minAge, now.getMonth(), now.getDate());
    return randomDate(minDate, maxDate);
}

// Format date as YYYY-MM-DD
function formatDate(date) {
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, "0");
    const day = String(date.getDate()).padStart(2, "0");
    return `${year}-${month}-${day}`;
}

// Generate multiple random dates
function generateRandomDates(count = 10, startDate = "2020-01-01", endDate = "2025-12-31") {
    return Array.from({length: count}, () =>
        formatDate(randomDate(startDate, endDate))
    );
}

// Using moment.js (npm install moment)
// const moment = require("moment");
// const randomMoment = moment(Math.random() * (
//     moment("2025-12-31").valueOf() - moment("2020-01-01").valueOf()
// ) + moment("2020-01-01").valueOf());

// Using date-fns (npm install date-fns)
// const { addDays, subDays } = require("date-fns");
// const pastDate = subDays(new Date(), Math.floor(Math.random() * 365));
// const futureDate = addDays(new Date(), Math.floor(Math.random() * 365));

// Usage examples
console.log("Random date:", formatDate(randomDate("2020-01-01", "2025-12-31")));
console.log("Past date:", formatDate(randomPastDate(30)));
console.log("Future date:", formatDate(randomFutureDate(90)));
console.log("Random birthday:", formatDate(randomBirthday()));
console.log("ISO format:", randomDateISO("2020-01-01", "2025-12-31"));
console.log("Batch:", generateRandomDates(5));

[EXPLANATION]

JavaScript's Date object uses milliseconds since Unix epoch. getTime() returns milliseconds, and Math.random() generates values between the range. The toISOString() method outputs ISO 8601 format (YYYY-MM-DDTHH:mm:ss.sssZ). Month indexes are 0-based (0=January, 11=December). Libraries like moment.js and date-fns provide timezone support, localization, and convenient manipulation methods. 86400000 milliseconds = 1 day.

Expected Output

Random date: 2023-07-15
Past date: 2024-11-17
Future date: 2025-03-15
Random birthday: 1985-04-23
ISO format: 2023-07-15
Batch: [ "2022-03-12", "2024-08-05", "2021-11-28", "2023-05-19", "2025-01-07" ]