Mastodawn

a colleague of mine, on a whim, told a coding agent to make a js implementation that passes all of test262. such a thing does not exist in the wild, despite hundreds of millions of investment in JS. the results are much better than i had expected https://p.ocmatos.com/blog/jsse-a-javascript-engine-built-by-an-agent.html

JSSE: A JavaScript Engine Built by an Agent - Notes & Code

JSSE is the first JavaScript engine to pass 100% of test262 non-staging tests. 170,000 lines of Rust. Zero lines written by me.

Notes & Code

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Philn 5d ago

@wingo In this becoming a trend? https://iangrunert.com/2026/03/22/writing-a-js-engine-using-claude-code

Writing a JS Engine using Claude Code

Over the past 2 months, I’ve been working on a JavaScript interpreter using Claude Code. It’s been an interesting side project, to learn about the weird corners of the ECMAScript spec while figuring out the edges of what Claude Opus 4.6 is capable of.

Ian Grunert

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Andy Wingo

@philn omg it is in the water