Function findFragmentTarget

core/src/components/router/utils/dom.ts:117–147

(fragment: string, shouldContinue: () => boolean)

 * last-to-first order preserves leaf-most preference for nested outlets.
 */
const findFragmentTarget = async (fragment: string, shouldContinue: () => boolean): Promise<HTMLElement | null> => {
  // CSS.escape is unavailable on very old WebViews; the fallback path uses
  // `getElementById` and drops the legacy `<a name>` branch.
  const canEscape = typeof CSS !== 'undefined' && typeof CSS.escape === 'function';
  const escaped = canEscape ? CSS.escape(fragment) : null;

  for (let i = 0; i < FRAGMENT_POLL_FRAMES; i++) {
    if (!shouldContinue()) return null;

    let candidates: HTMLElement[] = [];
    if (escaped !== null) {
      try {
        candidates = [...document.querySelectorAll<HTMLElement>(`#${escaped}, a[name="${escaped}"]`)];
      } catch {
        candidates = [...document.querySelectorAll<HTMLElement>(`#${escaped}`)];
      }
    } else {
      const byId = document.getElementById(fragment);
      if (byId !== null) candidates = [byId];
    }

    for (let j = candidates.length - 1; j >= 0; j--) {
      if (isInActivePage(candidates[j])) {
        return candidates[j];
      }
    }
    await nextFrame();
  }

  return null;
};

/**
 * Scrolls to the element whose id matches `fragment`, falling back to a legacy