Duktape
WebKit
Duktape | WebKit | |
---|---|---|
10 | 151 | |
5,830 | 7,456 | |
- | 1.7% | |
6.4 | 10.0 | |
about 1 month ago | 4 days ago | |
JavaScript | ||
MIT License | - |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
Duktape
- Roll your own JavaScript runtime, pt. 3
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How to Create a Modern C Project with CMake and Conan
Im my projects I search for single file libs.(like https://github.com/svaarala/duktape etc...)
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Is there anyway to bypass the limit of rand()?
Use lrand48(), or better, implement a high-quality RNG like PCG or splitmix64.
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Libgrapheme: A simple freestanding C99 library for Unicode
You can also refer to the Unicode routines of other small JS engines[1,2], those don’t use ICU either, although the implementations are mercilessly size-optimized (to put it politely) and restricted to what the target JS version requires (e.g. casemapping but no normalization).
[1] https://github.com/bellard/quickjs/blob/master/libunicode.c
[2] https://github.com/svaarala/duktape/blob/master/src-input/du...
- Duktape
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Nan Boxing
> memcpy from bytes to a NaN should work fine
Signaling NaNs are explicitly undefined in C11 F.2.1.: "This specification does not define the behavior of signaling NaNs." - and in practice may be "quieted" by conversion to Quiet NaNs, changing their bit patterns. Fast math optimization flags will also break the hell out of your code by assuming NaNs are impossible. I want to say there are more circumstances where optimizers and compiler generated code can butcher your NaN payloads, but I'd be working off recollected hearsay and I can't find a source, so don't quote me on that.
NaN boxing is common enough that, if you take the right precautions, a modern compiler should probably support it, maybe. NaN boxing is uncommon enough that, if your codebase needs to be sufficiently portable, you need an opt out for when it breaks. Let's review duktape's scars:
https://github.com/svaarala/duktape/blob/123d9426d5e5b36d5da...
https://github.com/svaarala/duktape/blob/5252b7a50611a3cb8bf...
https://github.com/svaarala/duktape/blob/224a0b89ca08a36e37e...
Note that "the right precautions" involve unions and proper integer types to avoid optimizer-invoked rewrites of the value and debugging when things go wrong, not simply YOLOing bytes into a double via memcpy. Note that debugging when it all goes terribly wrong can be quite painful. I've personally had the misfortune of being forced to debug duktape being built with fast math optimizatoins enabled on one "rare" platform + build configuration that wasn't caught by duktape's #if defined(__FAST_MATH__) checks linked above (wasn't Clang nor GCC, so go figure it didn't make the same #define)
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YouTube-dl has a JavaScript interpreter written in 870 lines of Python
I was expecting this to be about Duktape <https://github.com/svaarala/duktape>, but heh, for sure no. I'd bet $1 there's no way youtube-dl would switch, but I wonder if yt-dlp would?
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Optimizations Enabled by -ffast-Math
Fast math optimizations can break code like this by breaking isNaN.
I was porting a C++ project to a certain platform - and that platform enabled a -ffast-math equivalent by default in Release (but not Debug) builds! This broke duktape, a JS engine said project embedded, in some nasty and subtle ways. Instead of storing a number/pointer/??? (8 bytes) + type tag (4? bytes) for each dynamically typed JS value, duktape can bit-pack values into a single 8 byte "double" value by storing object/string handles as NaN values - this isn't an uncommon trick for dynamically typed scripting stuff:
https://github.com/svaarala/duktape/blob/c3722054ea4a4e50f48...
Naturally, the -ffast-math equivalent broke isNaN checks, which caused random object/string handles to be mistakenly reinterpreted as "numbers" - but only in Release builds, for this one particular platform, in one rarely taken branch, so neither QA nor CI caught it, leading to hours of manufacturing a repro case, stepping through an absurd amount of code, and then finally looking at the default build rules and facepalming.
Cursing the platform vendor under my breath, I overrode the defaults to align with the defaults of every other config x platform combination we already had: no fast math. If you want those optimizations, use SSE-friendly NaN-avoiding intrinsics - or, if you must use the compiler flags, ensure you do so consistently across build configs and platforms, perhaps limited to a few TUs or modules if possible. This allows you to have a chance at using your Debug builds to debug the resulting "optimizations".
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Can C++ and JS be used together?
Sure. For example, DukTape is an implementation of Javascript designed to be embedded in other projects. Google's V8 Javascript engine (used in Chrome), can also be embedded, see Node.Js for example.
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[AskJS] Do you use JavaScript on Microcontrollers? Which engine / interpreter?
- Duktape (4.8k stars)
WebKit
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GPU Compute in the Browser at the Speed of Native: WebGPU Marching Cubes
Multiple engineers are working on adding it back: https://github.com/WebKit/WebKit/pulls?q=is%3Apr+is%3Aclosed...
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HTML Streaming and DOM Diffing Algorithm
Since 2023 Chrome announced the View Transition API, and it looks like Safari is also going to support it soon.
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Towards memory safety with ownership checks for C
One heap per type.
Here’s an allocator optimized for that use case.
https://github.com/WebKit/WebKit/blob/main/Source/bmalloc/li...
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Bun, JavaScript, and TCO
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
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Show HN: Rem: Remember Everything (open source)
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...
- WebGPU now available for testing in Safari Technology Preview
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Disabling iOS Personalized Ads tells kernel to kill daemon every 3 seconds
No, it's unrelated.
https://github.com/WebKit/WebKit/commit/064df1a9f395f8c6e32c...
- Apple's Safari browser is still vulnerable to Spectre attacks
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Replacing WebRTC: real-time latency with WebTransport and WebCodecs
It's being worked on now: https://github.com/WebKit/WebKit/pull/17320
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iLeakage: Browser-Based Timerless Speculative Execution Attacks on Apple Devices
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...
What are some alternatives?
V8 - The official mirror of the V8 Git repository
chromium - The official GitHub mirror of the Chromium source
quickjs - Public repository of the QuickJS Javascript Engine.
otter-browser - Otter Browser aims to recreate the best aspects of the classic Opera (12.x) UI using Qt5
Lua - Lua is a powerful, efficient, lightweight, embeddable scripting language. It supports procedural programming, object-oriented programming, functional programming, data-driven programming, and data description.
cname-trackers - This repository contains a list of popular CNAME trackers
jerryscript - Ultra-lightweight JavaScript engine for the Internet of Things.
fingerprintjs - Browser fingerprinting library. Accuracy of this version is 40-60%, accuracy of the commercial Fingerprint Identification is 99.5%. V4 of this library is BSL licensed.
ChaiScript - Embedded Scripting Language Designed for C++
gecko-dev - Read-only Git mirror of the Mercurial gecko repositories at https://hg.mozilla.org. How to contribute: https://firefox-source-docs.mozilla.org/contributing/contribution_quickref.html
SWIG - SWIG is a software development tool that connects programs written in C and C++ with a variety of high-level programming languages.
uBlock-Safari - uBlock Origin - An efficient blocker for Chromium, Firefox, and Safari. Fast and lean.