アナウンサー

<%# Markup for the live-region announcer demo.
    The library owns one pair of polite/assertive live regions; triggers announce a
    message into the matching region via the announce action param (attribute-only).
    The regions are visually hidden (screen-reader only), so demo.js mirrors each
    announcement into a visible transcript for sighted viewers. %>
<%
  polite_msg = t("components.announcer.demo.polite_message")
  alert_msg = t("components.announcer.demo.assertive_message")
%>
<%# The controller wraps the whole demo so the attribute-only trigger buttons sit
    within its scope — a Stimulus action binds to a controller on the element or an
    ancestor, so triggers placed outside the controller element never fire. %>
<div class="announcer-demo" data-controller="stimeo--announcer">
  <div class="announcer-demo__controls">
    <button class="demo-trigger" type="button"
            data-action="click->stimeo--announcer#announce"
            data-stimeo--announcer-message-param="<%= polite_msg %>">
      <%= t("components.announcer.demo.announce_polite") %>
    </button>
    <button class="demo-trigger" type="button"
            data-action="click->stimeo--announcer#announce"
            data-stimeo--announcer-message-param="<%= alert_msg %>"
            data-stimeo--announcer-assertive-param="true">
      <%= t("components.announcer.demo.announce_assertive") %>
    </button>
  </div>

  <%# Place once per page. The consumer (this Playground) owns the visually-hidden
      styling via .visually-hidden; the library only writes the message text. %>
  <div class="visually-hidden"
       data-stimeo--announcer-target="polite" aria-live="polite" aria-atomic="true"></div>
  <div class="visually-hidden"
       data-stimeo--announcer-target="assertive" aria-live="assertive" aria-atomic="true"></div>

  <p class="announcer-demo__note"><%= t("components.announcer.demo.note") %></p>
  <%# Visible echo of what was announced (the live regions themselves are hidden). %>
  <ul class="announcer-log" data-announcer-log aria-hidden="true"></ul>
</div>

/*
 * Presentation-only styles for the live-region announcer demo.
 * The library only writes message text into the regions; this CSS owns the
 * visually-hidden ("sr-only") treatment and the visible transcript styling.
 */

.announcer-demo {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 32rem;
}

.announcer-demo__controls {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

/* The live regions use the shared `.visually-hidden` base primitive (kept in the
 * a11y tree, removed from view) — no per-demo duplication. */

.announcer-demo__note {
  margin: 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.announcer-log {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.announcer-log li {
  padding: 0.4rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 0.375rem;
  font-size: 0.9rem;
  font-family: ui-monospace, monospace;
}

// Consumer-side JS for the live-region announcer demo (demo-only).
// The live regions are visually hidden (screen-reader only), so this mirror echoes
// each announcement into a visible transcript for sighted viewers. It also shows
// the programmatic path: any code can announce by dispatching the custom event,
// e.g. window.dispatchEvent(new CustomEvent("stimeo--announcer:announce",
//   { detail: { message: "Saved", assertive: false } })).
const log = document.querySelector("[data-announcer-log]");
const regions = document.querySelectorAll("[data-stimeo--announcer-target]");

regions.forEach((region) => {
  const observer = new MutationObserver(() => {
    const text = (region.textContent || "").trim();
    if (!text || !log) return;
    const level = region.getAttribute("aria-live");
    const item = document.createElement("li");
    item.textContent = `[${level}] ${text}`;
    log.prepend(item);
  });
  observer.observe(region, { childList: true, characterData: true, subtree: true });
});