signals

JSX was also created with the intention of using traditional conditional/looping constructs, but that hasn't stopped Solid and Preact from repurposing it for fine grained reactivity. Preact's signal implementation has Solid-like Show/For components [1]. I won't speak for the author of the proposal, but given that Lit itself has special control flow mechanisms for conditionals and loops (the cache and repeat directives respectively [2][3]), I can't imagine the proposal being too opposed to these mechanisms. [1] https://github.com/preactjs/signals/blob/eae850a9f3aa62e505a... [2] https://lit.dev/docs/templates/conditionals/#caching-templat... [3] https://lit.dev/docs/templates/lists/#the-repeat-directive

Putting the runic terminology aside and looking into how the signal primitive is implemented should dispel the magic. I learned a lot from examining preact's implementation: https://github.com/preactjs/signals/blob/main/packages/core/...

Does someone know why the counter for this issue is at "70", but the repo only shows "21" issues in total? Maybe there are deleted issues that are not part of the total counter? https://github.com/preactjs/signals/issues?q=is%3Aissue

Update: it completely breaks with React 18 and strict mode enabled - https://github.com/preactjs/signals/issues/70

The implementation involves unsafe monkey-patching: 1. For React, a hook is injected into every single component (!) regardless of whether it uses signals or not via __SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED. 2. For React, React.createElement is patched so that it can render signal values as Text nodes. 3. For Preact, they claim it's using a "pluggable renderer", yet they monkey-patch the global shouldComponentUpdate (and they don't call the old one so they break other patchy libraries) [1] - https://github.com/preactjs/signals/blob/d25e8bac09c94ed3bad... [2] - https://github.com/preactjs/signals/blob/d25e8bac09c94ed3bad... [3] - https://github.com/preactjs/signals/blob/d25e8bac09c94ed3bad...

I read over the React integration here, and it seems like an unsafe approach to React 18+ by monkey-patching React internals state transitions, as well as mutating refs during rendering which can break during concurrent updates. Some abuse of the internals may be "safe" because React Devtools relies on this stuff, but I would be very nervous betting production correctness on this strategy long-term. Maybe it's worth it? Really hard call. Here's the details: https://github.com/preactjs/signals/blob/main/packages/react...