49K views · Oct 11, 2023 · 1:21:25 · 0 HN recommenders · 4 mentions · discussed 2023–2025
Andreas Kling live-codes a prototype JavaScript JIT compiler for the LibJS engine used in SerenityOS and Ladybird. He builds a standalone bytecode VM, a simple interpreter, and then a simple JIT in about 80 minutes.
Why Hacker News points people here: HN commenters cite it as a concrete example of how a skilled developer uses Copilot, mostly as fancy autocomplete for codebase-specific work.
“He basically uses it as a fancy autocomplete.”HN comment, 2025
“That's where Copilot shines, not for locating and copypasting answers from Stack Overflow.”
Example of Copilot helping with codebase-specific tasks.
The stuff Copilot helps me with is not the stuff SO could help me with. Check out 6:05 and 6:25 in this Andreas Kling video: this video That's where Copilot shines, not for locating and copypasting answers from Stack Overflow.
“I think the video illustrates what I mean with that as well.”
Example of Copilot assisting tedious codebase-specific work.
> The code is usually the same code I'd get a few web searches away My impression is that people normally don't use Copilot as a substitute for finding solutions (ChatGPT is much better for that), but as a way to help with otherwise tedious tasks that are really specific to your codebase. Check out 6:05 and 6:25 in this Andreas Kling video for a good example: this video Regarding your second point Copilot helps me when I least expects it. I think the video illustrates what I mean with that as well.
“He basically uses it as a fancy autocomplete.”
Shows Kling uses Copilot only as fancy autocomplete.
Ladybird is 425k LOC. Chromium is 3.5m LOC. Starting a new browser, using LLMs... Is not going to maintain enough context. Whilst Andreas does use Copilot a fair bit [0], he tends to do a line at a time, frequently disagree and rewrites his own, before prompting again. That is... He basically uses it as a fancy autocomplete. Not much else. [0] this video
“So not only was it a poor replacement for a macro, it didn't even generate the correct code!”
> Check out 6:05 and 6:25 in this Andreas Kling video for a good example: this video Oof. So not only was it a poor replacement for a macro, it didn't even generate the correct code!
