ecma262 VS quickjs

These aren't valid JavaScript (@@iterator would throw an error). They are actually internal Symbols used in JavaScript. They are used to implement features like iteration, instanceOf, and such internally. They actually might get removed or changed

Note that in previous editions, the ECMAScript® Language Specification used the term "lexical environment" before it decided to rename it to "Environment Record" so you might encounter this term in other definitions and tutorials.

For a new specification to be written, you need two things, a_ technical committee_, and a standard. The standard specification for JavaScript is called ECMA-262, and the technical committee is Technical Committee-39(TC39).

4. Proposed something else [ https://github.com/tc39/proposal-ptc-syntax ]

While apple is against Syntactic tail calls, they’re mainly just opposed to versions of it that would remove/unrequire the tail-call optimisation they already do: https://github.com/tc39/ecma262/issues/535

For the version of it that is backwards compatible, they wouldn’t need to do anything other than recognise it as valid syntax. Their main concern is that it "could add confusion with very little benefit."

The spec for STC has a critique of PTC:

- performance

- developer tools

- Error.stack

- cross-realm tail calls

- developer intent

See: https://github.com/tc39/proposal-ptc-syntax#issues-with-ptc

Apple's 2016 response as to why they won't implement STC is here: https://github.com/tc39/ecma262/issues/535

- STC is part of the spec and will take too long to change.

- Now that they've implemented support for PTC, they don't want to regress web pages that rely on it.

- They don't want to discourage vendors from implementing PTC by agreeing to STC.

- They don't want to introduce confusion.

Some of these arguments about confusion and delays seem wrong hindsight, since on every point things would have been better if they'd just agreed to the compromise of STC.

- It would have been part of the spec years ago

- STC would have had a clear way for web pages to know when tail calls could be relied on (and PTC would have been optional)

- Other vendors didn't implement PTC in any case, despite no agreement on STC

- There's even more confusion as things are now

It uses service workers to cache static files, by the time it opens up you already free to be offline, try toggle network switch to verify.

It has download link at bottom of the about page ([accdoo.app/about]) which you could then self host it by dropping into any static hosting services.

btw, the Pi feature was by-product from the original App but I won't expand here, if you'd like to learn more, please checkout its two Show HN post (39115559 and 39138957) previously.

[wiki]: https://en.wikipedia.org/wiki/Chudnovsky_algorithm

[quickjs/pi]: https://bellard.org/quickjs/pi.html

[pi_bigint.js]: https://github.com/bellard/quickjs/blob/master/examples/pi_b...

[accdoo.app/about]: https://accdoo.app/about#releases

[39115559]: https://news.ycombinator.com/item?id=39115559

[39138957]: https://news.ycombinator.com/item?id=39138957

Just go with quickjs, I think this is what you are looking for.

https://bellard.org/quickjs/

QuickJS

I think QuickJS, written in C, is a user-"friendly" starting point for implementing ECMA-262. Documentation QuickJS Javascript Engine.

There is a readme on the project's main page: https://bellard.org/quickjs/

The newsworthy bit here is that the activity seemed to have stalled for year or two and now Fabrice pushed a few fixes and made a new release.

Just to demonstrate GitHub repositories do not necessarily reflect upon a programmers' body of work, Fabrice Bellard has one (1) repository published on GitHub, quickjs. Compare the list of work on Bellard's home page https://bellard.org/.

> I am still confused, it's a JavaScript runtime intended to be deployed to JavaScript/Wasm runtimes?

Seemingly.

> Why does a JavaScript runtime need a JavaScript runtime?

Because if you want to create a Service Worker server for CloudFlare Workers and other JavaScript/Wasm runtimes, that's the only option for doing that AFAIK.

FWIW, this isn't a new idea. For example, Figma uses QuickJS (https://bellard.org/quickjs/) for their plug-in runtime: https://www.figma.com/blog/an-update-on-plugin-security/