How to dev

How to dev

What is the size impact of importing luxon - a date manipulation library

In this article, I'll take a look at the size impact of importing luxon. I'll check with both webpack & esbuild.

The code

Similar to the date-fns article in this series, I'm testing with a rather simple code:

// import trick from
import { DateTime } from "luxon/src/luxon";

console.log("Yesterday was",{ day: 1 }).toJSDate());

The import is modified from import { DataeTime } from 'luxon'; that you can find in the documentation. It improved the build size a bit, but not enough.

The build scripts

For my benchmark, I build code with:

webpack --mode=production

production mode set explicitly in webpack, and

esbuild src/index.js --outfile=dist/main.js --bundle --minify

Minification on in esbuild.

The benchmark

Both bundlers performed similarly in regards to size; of course, esbuild is much faster.


$ webpack --mode=production

asset main.js 58.3 KiB [emitted] [minimized] (name: main)
orphan modules 217 KiB [orphan] 24 modules
./src/index.js + 23 modules 216 KiB [built] [code generated]
webpack 5.47.1 compiled successfully in 1749 ms

$ stat dist/main.js 
  File: dist/main.js
  Size: 59710

The output size is 58.3 KiB


$ npm run esbuild  

> luxon-bundle-size@1.0.0 esbuild
> esbuild src/index.js --outfile=dist/main.js --bundle --minify

  dist/main.js  58.5kb

⚡ Done in 18ms
$ stat dist/main.js
  File: dist/main.js
  Size: 59929

The output size is 58.5KiB


You can find my test repository here.


In this article, we have seen a size impact of importing luxon to our project. Unfortunately, luxon doesn't support tree shaking, so for doing only 1 operation with it, we need to import the whole library. And for doing so, we get a serious size penalty to our project. I will not consider this library for my projects, and I'm really curious about use-cases when it's doing better than other libs discussed in this series - if you have any, please let me know in the comments.

Interested in reading more such articles from Marcin Wosinek?

Support the author by donating an amount of your choice.

Share this
Proudly part of