you-dont-need/you-dont-need-momentjs

★ 13,305JavaScriptAudience · developerComplexity · 1/5Setup · easy

Mindmap

mindmap
  root((repo))
    What it does
      Replace Moment.js
      Side-by-side examples
      Library comparison
    Alternatives Covered
      Native JS APIs
      date-fns
      Day.js
      Luxon
    Tools
      ESLint plugin
      Migration guidance
    Why Switch
      230kB bundle size
      Mutable API bugs
      No tree-shaking

mindmap root((repo)) What it does Replace Moment.js Side-by-side examples Library comparison Alternatives Covered Native JS APIs date-fns Day.js Luxon Tools ESLint plugin Migration guidance Why Switch 230kB bundle size Mutable API bugs No tree-shaking

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Things people build with this

USE CASE 1

Replace Moment.js in your JavaScript project with a lighter alternative to cut your bundle size from around 230kB.

USE CASE 2

Look up how to format, parse, or compare dates using native JavaScript without importing any library at all.

USE CASE 3

Use the included ESLint plugin to automatically flag Moment.js usage in your codebase and suggest replacements.

USE CASE 4

Choose between date-fns, Day.js, and Luxon by comparing their tree-shaking support, locale count, and bundle size.

Tech stack

JavaScriptdate-fnsDay.jsLuxonESLint

Getting it running

Difficulty · easy Time to first run · 5min

This is a reference guide and ESLint plugin, not a runtime library, no installation needed to read the comparison examples.

In plain English

You Don't Need Moment.js is a reference guide for JavaScript developers who want to stop relying on Moment.js for date and time work. Moment.js is a widely used library but has two significant drawbacks: it does not support tree-shaking, which means bundlers cannot remove the parts you don't use, leading to a bundle size around 230 kB even for simple uses. It also uses a mutable API, where operations like adding five days change the original date object in place rather than returning a new one, which is a known source of bugs. The main content of the repository is a side-by-side comparison of date operations in Moment.js versus several alternatives: native JavaScript browser APIs, date-fns, dayjs, and Luxon. Each section covers a specific task, such as parsing a date string, formatting a date for display, adding or subtracting time, comparing two dates, or checking whether a date falls within a range. The Moment.js code and the alternatives appear next to each other for easy comparison. A summary table near the top of the README compares the alternatives on factors like tree-shaking support, number of supported locales, bundle size, and timezone handling. This is intended to help you choose the right replacement for your situation rather than prescribing one answer. An ESLint plugin ships with the project. ESLint is a tool that checks your JavaScript code as you write it. The plugin can flag any Moment.js usage in your codebase and suggest equivalent code in one of the alternatives, which makes a gradual migration easier to manage. The full README is longer than what was shown.

Copy-paste prompts

Prompt 1

I'm migrating from Moment.js to date-fns. Show me equivalent code for parsing an ISO date string, formatting it as 'January 1 2024', and adding 5 days.

Prompt 2

Set up the you-dont-need-momentjs ESLint plugin in my React project to flag Moment.js imports and suggest Day.js alternatives.

Prompt 3

Compare Day.js and Luxon for a project that needs full timezone support and multiple locales. Which should I choose and why?

Prompt 4

Show me how to check if a date falls within a range using only native JavaScript Date APIs with no external libraries.

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