Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/wooorm/npm-esm-vs-cjs

Data on the share of ESM vs CJS on the public npm registry
https://github.com/wooorm/npm-esm-vs-cjs

cjs esm npm

Last synced: 3 days ago
JSON representation

Data on the share of ESM vs CJS on the public npm registry

Awesome Lists containing this project

README 

        
# npm-esm-vs-cjs



[![Build][build-badge]][build]



Data on the share of ESM vs CJS on the public npm registry.



## Contents



* [What is this?](#what-is-this)

* [When should I use this?](#when-should-i-use-this)

* [Data](#data)

* [Scripts](#scripts)

* [Contribute](#contribute)

* [Security](#security)

* [License](#license)



## What is this?



This repository contains (historical) data on [high-impact][] (popular) packages

and what kind of code they expose:



* ESM — such as `type: 'module'` in `package.json`

* dual — such as both `import` and `require` conditions in export map

* faux ESM — `module` field in `package.json`,

  supported by some old bundlers

* CJS — anything else (except for `@types/*`)



## When should I use this?



Use this data for rough insights on how the shift to ESM is progressing.

The data isn’t perfect though.



## Data



[`index.svg`][svg]:



![][svg]



[`index.csv`][csv]:



```csv

date,total,esm,dual,faux,cjs

2021-08-24,5617,341,95,832,4349

2021-11-09,5647,411,119,809,4308

2022-01-27,5686,439,149,809,4289

2022-08-01,5734,496,207,791,4240

2022-11-04,5747,518,216,785,4228

2023-02-06,6085,568,255,856,4406

2023-05-29,6240,630,417,783,4410

2023-08-24,6636,676,473,876,4611

2023-11-22,6818,734,510,881,4693

2024-02-20,7042,826,594,893,4729

2024-05-27,7042,819,736,826,4661

2024-08-28,7638,923,876,876,4963

2024-11-27,8087,942,1152,843,5150

```



> 👉 **Note**:

> the crawl of `2024-05-27` adjusts several packages that were

> previously classified incorrectly as dual.



> 👉 **Note**:

> crawls from before 2022-11-04 use the list of popular packages

> on the date of 2022-11-04,

> as I had the results of all packages,

> but not which of them were popular back then.

> Later dates will use a list of what’s popular on that date.



> 👉 **Note**:

> not all of these packages are popular.

> There are some false-positives,

> such that download counts can be gamed,

> and that `libraries.io` sometimes thinks that a fork of webpack or so is

> actually webpack.



> 👉 **Note**:

> while `@types/*` packages are filtered out in the above counts,

> it is likely that there are other packages included that aren’t really code,

> particularly in the CJS category (as that’s the default).



## Scripts



This repo includes scripts to crawl npm and analyze the results.

You need a `NPM_TOKEN` environment variable with a token to crawl npm.



[`script/crawl.js`][crawl] analyzes the `package.json` files of `latest`

releases of [high-impact][] npm packages.

This script finishes in about 5 minutes.

You should likely first contribute to `npm-high-impact`,

which can take like 24 hours to complete.



[`script/analyze.js`][analyze] analyzes the data files and generates SVG and

CSV files from them.

After running that,

please copy/paste the new `.csv` into this readme above.



## Contribute



Yes please!

See [How to Contribute to Open Source][contribute].



## Security



This package is safe.



## License



[MIT][license] © [Titus Wormer][author]



[build-badge]: https://github.com/wooorm/npm-esm-vs-cjs/workflows/main/badge.svg



[build]: https://github.com/wooorm/npm-esm-vs-cjs/actions



[contribute]: https://opensource.guide/how-to-contribute/



[license]: license



[author]: https://wooorm.com



[high-impact]: https://github.com/wooorm/npm-high-impact



[crawl]: script/crawl.js



[analyze]: script/analyze.js



[svg]: index.svg



[csv]: index.csv