[HN Gopher] JSSE: A JavaScript Engine Built by an Agent
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JSSE: A JavaScript Engine Built by an Agent
Author : tilt
Score : 18 points
Date : 2026-03-31 20:21 UTC (2 hours ago)
(HTM) web link (p.ocmatos.com)
(TXT) w3m dump (p.ocmatos.com)
| TheRealPomax wrote:
| Pretty neat as a real-sized-project experiment to see what a
| programming program can actually do.
| pseudosavant wrote:
| It is pretty incredible to me that in the pre-LLM/agent coding
| world, creating a new high-quality JS engine or browser seemed
| like it would likely never happen again. But now, any large
| company could build one if they wanted to. In a single digit
| number of months no less.
| dmitrygr wrote:
| Now do it without those pre-written tests. Spec only. Else, the
| writers of those tests deserve a LOT of credit.
| pseudosavant wrote:
| If there is one thing that that agents/LLMs have highlighted,
| it is how much credit those test writers do deserve. Teams that
| were already following a TDD-style approach seem to be able to
| realize value from agents most easily because of their tests.
|
| The tests are what enable: building a brand new JS runtime that
| works, rewriting a complex piece of code in a different
| language (e.g. Golang instead of TypeScript) that is more
| performant for that task, or even migrating off of an old stack
| (.NET WebForms) to something newer.
| Waterluvian wrote:
| This is _really cool_ to see and study. It's a great experiment.
|
| I think it doesn't really say a lot though. The hard part, in my
| opinion, is not making a new engine, it's making one that's worth
| using and will remain so for a long time.
|
| What I'd love to see next is how well (or poorly) this approach
| is at making the performance not terrible.
| Imustaskforhelp wrote:
| Great. the one-agent-one-human repository by embedding-shapes is
| certainly quite nice and I had tried to re-create the results
| (within golang) though and I had failed but even within that I
| feel like maybe I learnt a lot of things (Also got to talk with
| emsh on bsky!)
|
| It will also be very interesting to read simonw's comments on all
| of this too
| (https://news.ycombinator.com/item?id=46779522#46786824) when he
| had said:-
|
| No, I'm still waiting to see concrete evidence that the "swarms
| of parallel agents" thing is worthwhile. I use sub-agents in
| Claude Code occasionally - for problems that are easily divided -
| and that works fine as a speed-up, but I'm still holding out for
| an example of a swarm of agents that's really compelling.
|
| The reason I got excited about the Cursor FastRender example was
| that it seemed like the first genuine example of thousands of
| agents achieving something that couldn't be achieved in another
| way... and then embedding-shapes went and undermined it with
| 20,000 lines of single-agent Rust!
|
| (I wonder what Simon thinks now of this, because from my skim of
| this article, they do seem to mention some tidbits about
| parallelism, Either way, I think that these projects are really
| adventurous and there is still something novel in all of this.)
|
| (Edit: I have tried reading the blog post many times now but I am
| unable to understand how this is [working?] but something like
| cursor's project had turned to waste. Initially people were
| optimistic about cursor's project until emsh _really_ showed them
| that it wasn 't so good, I hope that this might not be the case
| here but still, I am just a bit confused as to why this in
| particular seems to work, kind of waiting for simon's post about
| it now :] )
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