Architecture & internals

func Counter(props CounterProps) gotsx.Node {
	return gotsx.Island("Counter", props, Counter_ssr(props))
}

func Counter_ssr(props CounterProps) gotsx.Node {
	var n float64 = props.Start            // useState → initial value
	setN := func(any) {}                   // setter → empty function
	var double float64 = (n * 2)
	return gotsx.El("button", nil,
		gotsx.Dyn(gotsx.Num(n)), gotsx.Text(" ×2 = "), gotsx.Dyn(gotsx.Num(double)),
		gotsx.If((n > 4), func() gotsx.Node { return gotsx.El("b", nil, gotsx.Text(" 🔥")) }))
}

• useState(start) → var n float64 = props.Start; the setter is an empty function.
• useEffect, event handlers, async functions → not generated.
• The reactive {n} → gotsx.Dyn (with a marker); static text → gotsx.Text.
• The island shell gotsx.Island(name, props, inner) serializes props into an attribute and turns on marker mode.

<gotsx-island name="Counter" props="{&quot;start&quot;:0}">
  <button>
    <!--$-->0<!--/--> ×2 = <!--$-->0<!--/-->
    <!--[--><!--]-->
  </button>
</gotsx-island>

The client receives JS of the same structure:

export default function Counter({ start }) {
  const [n, setN] = G.signal(start);
  const double = G.memo(() => (n() * 2));
  G.effect(() => { console.log(n()); });
  return G.el("button", { onClick: () => setN((n() + 1)) }, () => [
    G.text(() => n()), G.t(" ×2 = "), G.text(() => double()),
    G.cond(() => (n() > 4), () => G.el("b", null, () => [G.t(" 🔥")]))]);
}

G.el claims the next element, G.t claims the next text node, G.text claims the text between <!--$-->…<!--/--> and binds an effect, G.cond / G.each claim the <!--[-->…<!--]--> block. Children are deferred with thunks until after the parent is claimed, so the order is source order. No diff, no rebuild, the existing DOM is reused as-is.

• A host module is a Go value; hostgen reflects it into host.d.ts (for the editor) and host.json (for the compiler, with Go names and numeric types).
• What the dialect can do is exactly what Go exposes. Go is the single source of truth: routing, data, permissions, and actions all live in Go.
• The fence is at the type-check stage: a client importing host, a client importing a server component, await on the server, an unknown prop, member access on any — all compile errors.

Click a link → fetch the new page's HTML → idiomorph morphs the body over → islands survive by DOM identity (same name and props stay put, changed props rebuild, gone ones unmount). Form GET is the same; back/forward go through popstate; concurrent navigations honor only the last; a non-HTML response falls back to a full page load.