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Moment.js

The original JavaScript date library — now officially in maintenance mode.

Developer UtilitiesUtilityJavaScript
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What it is

Moment.js is a widely-used JavaScript library for parsing, validating, manipulating, and formatting dates and times. It simplifies working with dates across different browsers and time zones.

Moment.js allows you to create, parse, manipulate, and format dates and times easily. You can chain multiple operations, handle relative times, perform comparisons, and work with time zones using Moment Timezone.

Status
Maintenance mode — no new features
Licence
MIT

When to use it

The question documentation cannot answer for you — because it cannot recommend something else.

Reach for it when

  • Maintaining an existing codebase that already depends on it

Look elsewhere when

  • Any new project — the maintainers themselves recommend against it
  • Bundle size matters; Moment is large and not tree-shakeable
  • You need immutability — Moment objects are mutable, which causes real bugs

Installation

npm install moment

Getting started

The smallest useful thing you can do with it, and what each part means.

Getting current date and formatting
import moment from 'moment';
const now = moment();
console.log(now.format('YYYY-MM-DD HH:mm:ss'));
Creates a Moment object representing the current date and time, then formats it as a string.
Parsing a date string
const date = moment('2025-08-22', 'YYYY-MM-DD');
console.log(date.format('MMMM Do, YYYY'));
Parses a date string using a specified format and formats it in a human-readable form.

Advanced usage

Where the library earns its place over a simpler alternative.

Manipulating dates
let future = moment().add(7, 'days').subtract(2, 'hours');
console.log(future.format());
Adds 7 days and subtracts 2 hours from the current date.
Comparing dates
const date1 = moment('2025-08-22');
const date2 = moment('2025-09-01');
console.log(date1.isBefore(date2)); // true
console.log(date1.isAfter(date2)); // false
Compares two Moment objects to determine their chronological order.
Relative time
const past = moment('2025-08-15');
console.log(past.fromNow());
Displays the relative time from now, e.g., '7 days ago'.
Timezone handling
import 'moment-timezone';
const nyTime = moment.tz('2025-08-22 12:00', 'America/New_York');
console.log(nyTime.format());
Creates a Moment object in a specific timezone using Moment Timezone.

Errors and fixes

The failures you are most likely to hit, and what actually resolves them.

Invalid date
Ensure that the input string matches the expected format or use Moment's strict parsing mode.
Unexpected behavior across browsers
Use Moment.js instead of relying solely on the native Date object to handle inconsistencies.

Best practices

  • Use `.clone()` before modifying dates to avoid mutating original Moment objects.
  • Prefer ISO 8601 strings for parsing to ensure consistency.
  • Use Moment Timezone when working with different time zones.
  • Use relative time functions for user-friendly date displays.
  • Be aware that Moment.js is in maintenance mode; consider alternatives like date-fns or Luxon for new projects.

Alternatives

Comparable options, and the reason you would pick one over the other.

Background

Why it exists, and what it was reacting to.

Moment.js was created to provide a robust, reliable, and easy-to-use API for date manipulation in JavaScript. It became popular due to inconsistencies in the native Date object and its lack of convenient formatting, parsing, and timezone handling capabilities.

Related libraries

Others in Developer Utilities for JavaScript.

← All JavaScript librariesJavaScript guide