Migrating from Solid and SolidStart: Components and control flow

Solid	ShadowJS	What differs
`<Show when keyed fallback>`	`Show`	Same. Without `keyed`, a callback child receives an accessor; with `keyed` it receives the value.
`<Switch fallback>`, `<Match when>`	`Switch`, `Match`	Same. A child of `Switch` that is not a `Match` throws a `TypeError`.
`<For each fallback>`	`For`	Same for unkeyed rows: `(item, index) =>` where `item` is the plain value and `index` is an accessor. `For` over a store array updates on `push`, `splice` and index writes.
`<For each key={fn}>`	`For` with `key`	ShadowJS only. The callback then receives `item()` as an accessor, and a new object under the same key updates the row in place.
`<Index each>`	`Index`	Same: `(item, index) =>` with `item` an accessor and `index` a number.
`<Dynamic component>`, `createDynamic(component, props)`	`Dynamic`, `createDynamic(() => component, props)`	Same. `createDynamic` takes an accessor of the target. Tag names are validated and `script` is refused. Works in server rendering.
`<Portal mount>`	`Portal`	`mount` defaults to `document.body`. The content is inserted directly: no wrapper `div`, no `ref`. Events follow the DOM tree, not the component tree: a handler on a component ancestor does not see events from inside a portal. `useShadow` attaches a shadow root.
`<ErrorBoundary fallback>`	`ErrorBoundary`	Same: `fallback(error, reset)`.
`<Suspense fallback>`	`Suspense`	Same: the boundary around where a resource is read shows its fallback, and `onMount` and effects of its subtree wait until it resolves.
`lazy(() => import("./x"))`	`lazy(...)`	Same. `Component.preload()` resolves to the component function, not the module object.
`<ClientOnly fallback>` (SolidStart `clientOnly`)	`ClientOnly`	Renders `fallback` on the server and in the first client pass; the children replace it once the component has mounted. Compose with `lazy` for a lazy client-only component.
`<SuspenseList revealOrder tail>`	`SuspenseList`	Coordinates the `Suspense` boundaries below it so independent loads reveal in a set order.
`<NoHydration>`	`NoHydration`	The server renders the children without hydration keys; the browser leaves that markup untouched while the page hydrates. A client-side navigation renders them normally.
`@solidjs/meta` `<Title>`, `<Meta>`, `<Link>`, `<Style>`, `<Base>`, `useHead`	same names from `@shadow-js/web`	No `<MetaProvider>`: a per-document registry makes the wrapper unnecessary (remove it). Tags carry `data-shadow-head`. On the server they go to a `createServerHead()` collector passed as the `head` option, not into the returned markup; see Server rendering.