v0.25.1

Added

• lvt-* attributes are now extensible: LiveTemplateClient.registerAttribute().
  Adding an attribute used to mean forking this library — writing a dom/*.ts
  module, importing it into livetemplate-client.ts, and inserting a call at the
  right position in a hardcoded ~20-entry sequence. An app that wanted
  lvt-x:copy-to-clipboard had no supported way to get one.

  There are two layers. Most authors only need the declarative one: declare an
  attribute name and get called per element.

  <button lvt-x:copy="{{.ShareURL}}">Copy link</button>
  <script src="{{ lvtClientScriptURL }}" defer></script>
  <script>
    LiveTemplateClient.registerAttribute({
      attribute: "lvt-x:copy",
      onElementAdded(el, ctx) {
        el.addEventListener("click", () => navigator.clipboard.writeText(ctx.value));
      },
    });
  </script>

  The framework owns selector escaping, the DOM scan, per-element match
  tracking, empty-value rejection, and sweeping elements that lost the attribute
  or left the DOM — the sweep runs on every render, so onElementRemoved is
  never deferred — so the three classic mistakes (no sweep, listeners stacking
  on every render, a captured transport that dies at reconnect) are not
  reachable from this layer. ctx.value and ctx.send are live accessors, so a
  listener wired once still reads the current attribute value and dispatches
  through the current transport.

  Set needsServerChannel: true to get ctx.send; the message routes through
  the same path an lvt-on:click action uses, and the server cannot tell the
  difference. No server-side registration, no new wire message type, no build
  step.

  A selectors + setup()/teardown() escape hatch covers handlers with
  cross-element state; every built-in uses it, so an author is never on a lesser
  API than the framework itself.

  Registration is static and late registration is supported: calling
  registerAttribute after the client has connected runs the handler against
  the live DOM immediately, rather than waiting for the next render. That is the
  only sequence available to a second <script>, because autoInit() has
  already connected by the time one evaluates.

  Exported types: AttributeHandler, DeclarativeHandler, LowLevelHandler,
  ElementContext, SetupContext, SendFn, HandlerCategory.

  registerAttribute is deliberately unauthenticated, and grants no capability
  a page script did not already have: window.liveTemplateClient.send() has
  always been public, so any script with page access could already dispatch
  arbitrary actions. Server-side authorization is unchanged and remains the
  boundary that matters.

  Two limits worth knowing before you build on this. Registration is
  append-only — there is no unregisterAttribute yet, so a dev server that
  hot-reloads a handler bundle accumulates one live handler per reload; the
  production <script defer> pattern, where a bundle evaluates once, is
  unaffected. And dispose() runs when the last client on the page
  disconnects, because the registry is shared by all of them; per-client
  cleanup belongs in teardown(root), which runs for each client as it goes.

Changed

• Every built-in attribute handler now runs through that same registry. The
  hardcoded post-render call sequence and the matching disconnect() teardown
  list are gone, replaced by a loop over registered handlers. No attribute
  changed its spelling, semantics, or server-side treatment, and no template
  needs an edit; all 824 pre-existing tests pass unmodified.

Installation

npm

npm install @livetemplate/client@0.25.1

CDN

<script src="https://cdn.jsdelivr.net/npm/@livetemplate/client@0.25.1/dist/livetemplate-client.browser.js"></script>

Related Releases

This release follows the LiveTemplate core library version 0.25.x

• Core Library: https://github.com/livetemplate/livetemplate
• CLI Tool: https://github.com/livetemplate/lvt
• Examples: https://github.com/livetemplate/examples