continuation VS WebKit

JavaScript generators are unmined gold! We've done a lot of usage of JavaScript generators as delimited continuations; using them to implement the classic shift/reset operations in JavaScript. https://github.com/thefrontside/continuation

Built on those delimited continuations is structured concurrency for JavaScript (https://frontside.com/effection)

While working on effection (https://github.com/thefrontside/effection) we spent a bunch of time ensuring that our delimited continuations could handle deep recursive call stacks in Deno.

PR: https://github.com/thefrontside/continuation/pull/11

TCO would have definitely simplified this issue.

What’s worse is hitting maximum memory callstack exception is very tricky to catch and is not reliable across runtimes. So when a user hits it it can be tricky to track down.

- https://github.com/thefrontside/continuation

- https://github.com/thefrontside/effection/tree/v3

- https://github.com/neurosnap/starfx

The last one intends to replace redux-saga using DCs.

Here’s a presentation I gave recently talking about DCs in typescript: https://youtu.be/uRbqLGj_6mI?si=XI0JNMKMoO2VHMvM

These libraries rely on deliminited continuations:

https://github.com/thefrontside/continuation

Because of this tiny implementation we are able to express any async flow construct with less code than relying on something like async/await or callbacks.

Multiple engineers are working on adding it back: https://github.com/WebKit/WebKit/pulls?q=is%3Apr+is%3Aclosed...

Since 2023 Chrome announced the View Transition API, and it looks like Safari is also going to support it soon.

One heap per type.

Here’s an allocator optimized for that use case.

https://github.com/WebKit/WebKit/blob/main/Source/bmalloc/li...

To use this in Bun, you’d have to start Bun with the environment variable “BUN_JSC_useDollarVM=1” and then $vm.createBuiltin(mySourceCodeString)

When using this intrinsic, if any of the arguments are incorrect or it cannot otherwise enable it, the entire process will probably crash. In debug builds of JSC it will have a nicer assertion failure but that is not enabled in release builds

Example code: https://github.com/WebKit/WebKit/blob/17351231b4dedb62d81721...

also happy to answer any questions about Bun

Ah, good, let me introduce you to the wonderful world of the Chrome Devtools Protocol! (fka Chrome Remote Debugging Protocol)

I love this API for almost everything browser related. I built my RBI product atop this (BrowserBox: https://dosyago.com), and I think it's a drastically underrated API.

Also, it works out of the box in Edge, Brave, Chromium, and many parts of CRDP are supported by Firefox and Safari^1

1: See for example: https://github.com/WebKit/webkit/tree/main/Source/JavaScript...

No, it's unrelated.

https://github.com/WebKit/WebKit/commit/064df1a9f395f8c6e32c...

It's being worked on now: https://github.com/WebKit/WebKit/pull/17320

It is different. The cross-site navigation flag is a couple of years old. It was enabled by default for iOS in November 2018 for example https://github.com/WebKit/WebKit/commit/e191fc8c412850cb9fd0...