[JUST_A_STORY] The recent story behind core-js

paulishca · February 15, 2023, 6:34am

To be frank, this was heart breaking from the way it is being told … but I might not have the entire picture. Open Collective seems to say something different about the scale of financials behind the library as some people claim in Twitter.

I post this because it seems to be one of the hottest “news” in JS at the moment.

I seem to use core-js (it is really hard not too after you do a couple of npm installs) in mup-aws-beanstalk and babel-plugin-transform-class-properties

github.com

zloirock/core-js/blob/master/docs/2023-02-14-so-whats-next.md

<p align="center"><img alt="core-js" src="https://user-images.githubusercontent.com/2213682/146607186-8e13ddef-26a4-4ebf-befd-5aac9d77c090.png" /></p>

# So, what's next?

Hi. I am (**[@zloirock](https://github.com/zloirock)**) a full-time open-source developer. I don't like to write long posts, but it seems this is high time to do it. Initially, this post was supposed to be a post about the start of active development of the new major version of `core-js` and the roadmap (it was moved to [the second half](#roadmap)), however, due to recent events, became a really long post about many different things... I'm fucking tired. Free open-source software is fundamentally broken. I could stop working on this silently, but I want to give open-source one last chance.

## What is [`core-js`](https://github.com/zloirock/core-js)?

- It is the most popular and the most universal polyfill of the JavaScript standard library, which provides support for the latest ECMAScript standard and proposals, from ancient ES5 features to bleeding edge features like [iterator helpers](https://github.com/tc39/proposal-iterator-helpers), and web platform features closely related to ECMAScript, like `structuredClone`.
- It is the most complex and comprehensive polyfill project. At the time of publishing this post, `core-js` contains about a half thousand polyfill modules with different levels of complexity - from `Object.hasOwn` or `Array.prototype.at` to `URL`, `Promise` or `Symbol` — that designed to work together. With another architecture, each of them could be a separate package - however, it is not so convenient.
- It is maximally modular — you can easily (or even automatically) choose to load only the features you will be using. It can be used without polluting the global namespace (someone calls such a use case "ponyfill").
- It is designed for integration with tools and provides all that's required for this — for example, `@babel/preset-env`, `@babel/transform-runtime`, and similar SWC features are based on `core-js`.
- It is one of the main reasons why developers can use modern ECMAScript features in their development process each day for many years, but most developers just don't know that they have this possibility because of `core-js` since they use `core-js` indirectly as it's provided by their transpilers / frameworks / intermediate packages like `babel-polyfill` / etc.
- It is not a framework or a library, which usage require the developer to know their API, periodically look at the documentation, or at least remember that he or she is using it. Even if developers use `core-js` directly — it’s just some lines of import or some lines in the configuration (in most cases — with mistakes, since almost no one read the documentation), after that, they forget about `core-js` and just use provided by `core-js` features from web-standards — but sometimes this is the most of JS standard library that they use.

[About 9 billion NPM downloads / 250 million NPM downloads for a month](https://npm-stat.com/charts.html?package=core-js&package=core-js-pure&package=core-js-bundle&from=2014-11-18), 19 million dependent GitHub repositories ([global](https://github.com/zloirock/core-js/network/dependents?package_id=UGFja2FnZS00ODk5NjgyNDU%3D) ⋃ [pure](https://github.com/zloirock/core-js/network/dependents?package_id=UGFja2FnZS00MjYyOTI0Ng%3D%3D)) - big numbers, however, they do not show the real spread of `core-js`. Let's check it.

I wrote [a simple script](https://github.com/zloirock/core-js/blob/master/scripts/usage/usage.mjs) that checks the usage of `core-js` in the wild by the Alexa top websites list. We can detect obvious cases of `core-js` usage and used versions (only modern).

<p align="center"><img alt="usage" src="https://user-images.githubusercontent.com/2213682/218452738-859e7420-6376-44ec-addd-e91e4bcdec1d.png" /></p>

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