By default LLMs will start creating a tangled hard to test mess of javascript. But if you ask them to do TDD they will, and if you give them access to Playwright and have them write playwright tests this can all work.

The advantage for the LLM is the same for humans. With the right abstractions, code can be written quicker and more robustly.

To get more hands off with LLMS you really want to have a lot of engineering rigor. A big part of that is a focus on tests. If your abstractions make testing easier, your results will be a lot better. For Javascript the more you can test logic without DOM manipulation and without playwright tests, the better.

I found LLMs to be default to and be pretty good at working with HTMX, but not great (mostly lots of state synchronization issues). The focus on DOM markup of HTMX does not lend itself well to simplifying testing. I don't claim to be an expert at HTMX, but I don't see a separate section on testing in their documentation.

I am trying out the foldkit framework because it makes a lot more testable outside the DOM. Its probably too heavy weight for most humans (and for simple apps- it only seems appropriate for client-side apps), but I will see how well LLMs can work with it.