フォーカス管理ユーティリティ

<%# Focus-scope demo: the Activate button sits outside the scope, so it invokes the
    controller's activate action through the playground's exposed Stimulus app
    (window.Stimulus) in demo.js. Once active, Tab cycles within the box, focus lands on
    the initial target, and Escape or the Release button (a descendant, wired with a plain
    data-action) ends it and restores focus. inert is left off so the soft boundary does
    not isolate the rest of the catalog page. The library only manages focus and reflects
    data-focus-trapped; demo.css owns the look. %>
<div class="focus-demo">
  <button
    type="button"
    class="demo-trigger"
    data-focus-demo-activate
    aria-pressed="false"
    data-activate-label="<%= t('components.focus.demo.activate') %>"
    data-deactivate-label="<%= t('components.focus.demo.deactivate') %>">
    <%= t("components.focus.demo.activate") %>
  </button>

  <div class="focus-demo__scope" data-controller="stimeo--focus">
    <p class="focus-demo__hint"><%= t("components.focus.demo.hint") %></p>
    <label class="focus-demo__field">
      <span><%= t("components.focus.demo.field") %></span>
      <input type="text" class="demo-input" data-stimeo--focus-target="initial" />
    </label>
    <div class="focus-demo__bar">
      <button type="button" class="demo-trigger"><%= t("components.focus.demo.inner") %></button>
      <button type="button" class="demo-trigger" data-action="click->stimeo--focus#deactivate">
        <%= t("components.focus.demo.release") %>
      </button>
    </div>
  </div>
</div>

/*
 * Presentation-only styles for the focus-scope demo. The library manages focus and
 * reflects data-focus-trapped; this CSS lays out the scope and highlights it while the
 * trap is active so the boundary is visible.
 */

.focus-demo {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: flex-start;
}

.focus-demo__scope {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  width: 100%;
  max-width: 24rem;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
}

/* Make the active boundary obvious. */
.focus-demo__scope[data-focus-trapped] {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(var(--vital-rgb), 0.2);
}

.focus-demo__hint {
  margin: 0;
  color: var(--color-text-muted);
}

.focus-demo__field {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.focus-demo__field input {
  padding: 0.375rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.375rem;
}

.focus-demo__bar {
  display: flex;
  gap: 0.5rem;
}

// Focus-scope demo (consumer-side JS).
//
// The Activate button sits outside the (trapped) scope, so a plain data-action can't
// reach the controller. The playground exposes its Stimulus application as
// window.Stimulus, so we fetch the controller instance and call its activate() action.
// Release (inside the scope) uses a normal data-action, and Escape works on its own.
document.querySelectorAll(".focus-demo").forEach((root) => {
  const scope = root.querySelector('[data-controller~="stimeo--focus"]');
  const button = root.querySelector("[data-focus-demo-activate]");
  if (!scope || !button) return;
  // Idempotent: Turbo can re-run this inline module on navigation; wire each root once. The
  // marker is a property, not an attribute: Turbo copies attributes into its page snapshot,
  // so an attribute one comes back set on a restored page whose elements carry no listeners.
  if (root.demoWired) return;
  root.demoWired = true;

  const controller = () =>
    window.Stimulus?.getControllerForElementAndIdentifier(scope, "stimeo--focus");
  // The external button toggles the scope on/off and stays in sync with the controller's
  // activate/deactivate events, so its label is correct even when Escape or the inner
  // Release ends the scope.
  const sync = (active) => {
    button.textContent = active ? button.dataset.deactivateLabel : button.dataset.activateLabel;
    button.setAttribute("aria-pressed", String(active));
  };
  button.addEventListener("click", () => {
    if (scope.hasAttribute("data-focus-trapped")) controller()?.deactivate();
    else controller()?.activate();
  });
  scope.addEventListener("stimeo--focus:activate", () => sync(true));
  scope.addEventListener("stimeo--focus:deactivate", () => sync(false));
  sync(false);
});