date-light

The date helpers you actually ship. Nothing else.

39 fully typed date utilities in ~2.19 KB minzipped. Zero dependencies. Immutable by default.

Install · Why date-light? · Docs · API

Why date-light?

Most apps only need a small, predictable slice of date-fns: format a date, parse input, add a few days, compare ranges, snap to day/week/month boundaries.

date-light keeps that slice tiny:

• 2.19 KB minzipped for 39 common utilities
• Zero runtime dependencies
• TypeScript-first with generated declarations
• Immutable functions that never mutate input dates
• date-fns-style API surface for the common calls people reach for most
• ESM + CJS package entrypoints verified before release

import { addDays, differenceInDays, format, startOfWeek } from "date-light";

const launch = new Date(2026, 5, 30, 14, 30);
const reminder = addDays(launch, -7);

format(launch, "yyyy-MM-dd HH:mm"); // "2026-06-30 14:30"
format(startOfWeek(launch), "yyyy-MM-dd"); // "2026-06-29"
differenceInDays(launch, reminder); // 7

Install

npm install date-light

yarn add date-light
pnpm add date-light
bun add date-light

Works in Node.js 18+ and modern browsers.

What You Get

import {
  format,
  parseISO,
  addDays,
  addMonths,
  differenceInDays,
  isBefore,
  isWeekend,
  startOfDay,
  endOfMonth,
} from "date-light";

| Area | Utilities | | -------------- | --------------------------------------------------------------- | | Format & parse | format, parseISO, parse | | Add & subtract | addDays, addMonths, addYears, addHours, subDays, more | | Differences | differenceInDays, differenceInMonths, differenceInYears | | Compare | isBefore, isAfter, isEqual, isSameDay, isSameMonth | | Query | isWeekend, isLeapYear, isValid, getDaysInMonth | | Start & end | startOfDay, endOfWeek, startOfMonth, endOfYear, more |

Full list: API Reference

The Tradeoff

date-light is intentionally not a calendar platform. It does not include locales, timezone databases, duration objects, plugins, or chainable wrappers.

That is the point. For those jobs, use Intl, Temporal, Luxon, or date-fns directly. For common app date utilities, keep the dependency small.

Size

| Library | minzipped | Note | | ----------------------- | ----------- | ---------------------------------- | | date-light | 2.19 KB | 39 functions, fully tree-shakeable | | dayjs | 2.97 KB | Core only | | date-fns (20 functions) | 18.34 KB | Same common-operation comparison | | date-fns (full) | 261.3 KB | Full package |

date-light (39 functions) is 8.4x smaller than importing 20 comparable date-fns functions and 1.4x smaller than dayjs core.

Documentation

• Getting Started
• API Reference
• Migration from date-fns
• Benchmarks
• Development

License

MIT 2026

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