Limitations & roadmap

Limitations & notes

Declarative Shadow DOM support. All current evergreen browsers parse <template shadowrootmode>. For legacy browsers, ship a small DSD polyfill.
No lifecycle on the server. Only template() runs (purely, from properties); connected(), watchers, effects and DOM measurement do not. Components whose initial markup depends on runtime state beyond their declared properties will render that state's default until the client hydrates. See Rendering & hydration.
State transport. element-js' ejs:key / serializeState plumbing can carry server state to the client; wiring it through this transformer is on the roadmap (see below).

Tracked in the repo's TASKS.md. Highlights:

State transport (T-007) — assign each rendered component a stable, deterministic ejs:key, collect each component's serializeState() output into a single <script type="ejs/json">, and handle shared Store references, so stateful components hydrate with their server-rendered state instead of re-deriving it from property defaults.
Async per-component property provider (T-009) — an optional hook to supply server-fetched / async props for a component before its SSR render, merged ahead of HTML attributes over element defaults.