Доработать UI уведомлений

2026-08-21 14:06:19 +03:00
parent 23bdadab56
commit 19362b950a
7 changed files with 754 additions and 42 deletions
@@ -0,0 +1,141 @@
+function resolveElement(value) {
+  return typeof value === 'function' ? value() : value;
+}
+
+function buildArrowIcon() {
+  const icon = document.createElement('span');
+  icon.className = 'scroll-to-bottom-btn__icon';
+  icon.setAttribute('aria-hidden', 'true');
+  icon.textContent = '↓';
+  return icon;
+}
+
+export function attachScrollToBottomButton({
+  scrollContainer,
+  mountTarget = document.querySelector('.app-shell'),
+  thresholdPx = 160,
+  title = 'Вниз',
+} = {}) {
+  const target = resolveElement(mountTarget);
+  if (!(target instanceof Element)) {
+    return {
+      button: null,
+      refresh() {},
+      cleanup() {},
+    };
+  }
+
+  const button = document.createElement('button');
+  button.type = 'button';
+  button.className = 'scroll-to-bottom-btn';
+  button.title = title;
+  button.setAttribute('aria-label', 'Прокрутить ленту вниз');
+  button.append(buildArrowIcon());
+  target.append(button);
+
+  let disposed = false;
+  let boundContainer = null;
+  let resizeObserver = null;
+  let mutationObserver = null;
+  let refreshFrame = 0;
+
+  const hide = () => {
+    button.classList.remove('is-visible');
+    button.setAttribute('aria-hidden', 'true');
+  };
+
+  const scheduleRefresh = () => {
+    if (disposed || refreshFrame) return;
+    refreshFrame = window.requestAnimationFrame(() => {
+      refreshFrame = 0;
+      refresh();
+    });
+  };
+
+  const unbindContainer = () => {
+    boundContainer?.removeEventListener('scroll', scheduleRefresh);
+    resizeObserver?.disconnect();
+    mutationObserver?.disconnect();
+    resizeObserver = null;
+    mutationObserver = null;
+    boundContainer = null;
+  };
+
+  const bindContainer = () => {
+    const nextContainer = resolveElement(scrollContainer);
+    if (!(nextContainer instanceof Element)) {
+      if (boundContainer) unbindContainer();
+      return null;
+    }
+    if (nextContainer === boundContainer) return boundContainer;
+
+    unbindContainer();
+    boundContainer = nextContainer;
+    boundContainer.addEventListener('scroll', scheduleRefresh, { passive: true });
+
+    if (typeof ResizeObserver === 'function') {
+      resizeObserver = new ResizeObserver(scheduleRefresh);
+      resizeObserver.observe(boundContainer);
+    }
+
+    if (typeof MutationObserver === 'function') {
+      mutationObserver = new MutationObserver(scheduleRefresh);
+      mutationObserver.observe(boundContainer, { childList: true, subtree: true });
+    }
+
+    return boundContainer;
+  };
+
+  function refresh() {
+    if (disposed) return;
+    const container = bindContainer();
+    if (!container) {
+      hide();
+      return;
+    }
+
+    const scrollHeight = Number(container.scrollHeight || 0);
+    const clientHeight = Number(container.clientHeight || 0);
+    const scrollTop = Number(container.scrollTop || 0);
+    const maxScrollTop = Math.max(0, scrollHeight - clientHeight);
+    const distanceToBottom = Math.max(0, maxScrollTop - scrollTop);
+    const shouldShow = maxScrollTop > 8 && distanceToBottom > Math.max(24, Number(thresholdPx || 0));
+
+    button.classList.toggle('is-visible', shouldShow);
+    button.setAttribute('aria-hidden', shouldShow ? 'false' : 'true');
+  }
+
+  const scrollToBottom = () => {
+    const container = bindContainer();
+    if (!container) return;
+    if (typeof container.scrollTo === 'function') {
+      container.scrollTo({ top: container.scrollHeight, behavior: 'smooth' });
+    } else {
+      container.scrollTop = container.scrollHeight;
+    }
+    scheduleRefresh();
+  };
+
+  button.addEventListener('click', scrollToBottom);
+  window.addEventListener('resize', scheduleRefresh);
+  window.visualViewport?.addEventListener('resize', scheduleRefresh);
+  window.requestAnimationFrame(refresh);
+
+  return {
+    button,
+    refresh: scheduleRefresh,
+    cleanup() {
+      if (disposed) return;
+      disposed = true;
+      if (refreshFrame) {
+        window.cancelAnimationFrame(refreshFrame);
+        refreshFrame = 0;
+      }
+      unbindContainer();
+      window.removeEventListener('resize', scheduleRefresh);
+      window.visualViewport?.removeEventListener('resize', scheduleRefresh);
+      button.removeEventListener('click', scrollToBottom);
+      button.remove();
+    },
+  };
+}