Edge.js: Run Node apps inside a WebAssembly sandbox
wasmer.io69 points by syrusakbary 5 hours ago
69 points by syrusakbary 5 hours ago
Hi HN!
I'm Syrus, from Wasmer. We built Edge.js in a few weeks after different trials trying to bring Node.js to the Edge. We used AI and Codex heavily for this project, as otherwise the timeline would have spanned to a year plus to develop.
The summary of this announcement is that Edge.js:
* Runs using WebAssembly when in `--safe` mode
* It's fully compatible with Node.js (passing all their spec tests for non-VM modules)
* It has a pluggable JS engine architecture: can work with V8, Javascript, SpiderMonkey, QuickJS, Hermes, etc.
Maybe I’m just dense, but it says the fs module is fully supported, so what happens when I try to read a file from disk if the app is fully sandboxed?
Only the current working directory will be exposed/mounted to the runtime (we do this to facilitate the DX when running local files without requiring the user to add extra flags).
As a fun exercise, you can try reading process.cwd() from edge in --safe mode and without it.
Awesome project!
Dumb question: could you run this in frontend js using the browser's js engine and wasm environment similar to WebContainers? Maybe `fs` is just in-memory, and some things like forking are disabled. It'd be cool to have "nodejs" in the web!
I work on a project that does exactly that (and more): https://browserpod.io/.
Currently it supports Node, but we plan to add Python, Ruby, git, and more.
You can see it in action in this demo: https://vitedemo.browserpod.io
More info here: https://labs.leaningtech.com/blog/browserpod-10
Ah and kudos to Syrus and his team for this release. Edge.js's architecture seems to have many similarities with BrowserPod. I see it as proof that we are both going in the right direction!
It’s not a dumb question at all.
And yes, it will allow running Node.js apps fully on the browser, in a way that’s more compatible than any other alternative!
Stay tuned!
Do you have any specific test case that you would consider "very challenging" on the compatibility side? I'd be curious to check if BrowserPod can support that already.
>in a way that’s more compatible than any other alternative
I can see where that's going.
Awesome. I want to msg. you on LinkedIn but can't.
Very cool project!
Question regarding the pluggable js engine: I have an electron app where I'm currently using QuickJS to run LLM-generated code. Would edge.js be able (theoretically) to use electron's v8 to get a "sanboxed within electron" execution environment?
Yes, this should be fully possible.
We actually believe Edge.js will a great use case for LLM-generated code.
naively, based on their install.sh script, you'd pick the correct edge.js executable and shell out to that. I'm sure there's some more integral means, but if you wanted a quick test, that should be easily setup.
Very interesting! On what platforms can this run? If it can run on iOS, how would you handle attempts to access to the file system or networking, is this already wired in somehow? If not is it easy to add custom handlers to handle these actions?
Yes, it could run in iOS (using JavascriptCore, V8 in jitless mode, or QuickJS), although we don't have a prototype app yet.
It should probably take a few hours with AI to get a demo for it :)
It's a bit confusing.
Roughly:
* a refactor of Node.js, but using a standardized API for JS engine interop * Integration with the Wasmer CLI so it will run JS with v8 but, everything else in Webassembly
Interesting idea.
Could be a much lighter weight way to sandbox JS...
We are so deep into the weeds that sometimes is hard for us to realize that maybe we are not explaining in the best terms.
What was the most confusing thing in the blogpost? I'd like to polish a bit more to make it clearer! Thanks a lot!
Hi Syrusakbary, I have to admit I still do not fully understand what this is.
First, I could not find usage examples on the edgejs.org page and the docs link points to the node docs, why?
If I head to github, there are some usage examples, but they confuse me more.
The first example: $ edge server.js led me to think that this is a node replacement that runs in a webassembly sandbox, so completely isolated. But why the need of --safe then? What's the difference between using it and not using it?
But the next examples creates more confusion to me: $ edge node myfile.js $ edge npm install $ edge pnpm run dev
What is this doing? I thought that edge was a node replacement, interpreting and running javascript files, but it's now running executables (node, npm)... what is that? What happens when I run npm install... where does it install files? What's the difference between running edge node myfile.js and edge myfile.js?
Hope this helps.
> I could not find usage examples on the edgejs.org page and the docs link points to the node docs, why?
This was intentional, as a demonstration that Edge and Node should not diverge a bit. You should be able to replace `node` with `edge` in your terminal and have things running, so that's why we point to the Node.js docs.
> But why the need of --safe then? What's the difference between using it and not using it?
Edge.js currently runs without a sandbox by default. The main reason for this is two fold: native currently performs a bit better than with the Wasm sandbox (about 10-20% better), and because we wanted to polish more the Wasm integration before offering it as default.
> $ edge pnpm run dev > What is this doing?
This is making the `node` alias available for anything that you put after edge. This allows pnpm to use the edge `node` alias instead of your platform node.
Things will be installed as usual, in your `node_modules` directory
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