react-ui-patterns

React UI 模式

核心原则

1. 绝不展示过时的 UI - 仅在真正加载时才显示加载指示器
2. 始终暴露错误 - 用户必须知道何时出错
3. 乐观更新 - 让 UI 感觉即时响应
4. 渐进式披露 - 内容可用时即展示
5. 优雅降级 - 部分数据总比没有数据好

加载状态模式

黄金法则

仅当没有数据可显示时才显示加载指示器。

// CORRECT - Only show loading when no data exists
const { data, loading, error } = useGetItemsQuery();

if (error) return <ErrorState error={error} onRetry={refetch} />;
if (loading && !data) return <LoadingState />;
if (!data?.items.length) return <EmptyState />;

return <ItemList items={data.items} />;

// WRONG - Shows spinner even when we have cached data
if (loading) return <LoadingState />; // Flashes on refetch!

加载状态决策树

Is there an error?
  → Yes: Show error state with retry option
  → No: Continue

Is it loading AND we have no data?
  → Yes: Show loading indicator (spinner/skeleton)
  → No: Continue

Do we have data?
  → Yes, with items: Show the data
  → Yes, but empty: Show empty state
  → No: Show loading (fallback)

骨架屏 vs 加载指示器

使用骨架屏的场景	使用加载指示器的场景
已知内容形状	未知内容形状
列表/卡片布局	模态操作
初始页面加载	按钮提交
内容占位符	内联操作

错误处理模式

错误处理层级

1. Inline error (field-level) → Form validation errors
2. Toast notification → Recoverable errors, user can retry
3. Error banner → Page-level errors, data still partially usable
4. Full error screen → Unrecoverable, needs user action

始终显示错误

关键：绝不要静默吞掉错误。

// CORRECT - Error always surfaced to user
const [createItem, { loading }] = useCreateItemMutation({
  onCompleted: () => {
    toast.success({ title: 'Item created' });
  },
  onError: (error) => {
    console.error('createItem failed:', error);
    toast.error({ title: 'Failed to create item' });
  },
});

// WRONG - Error silently caught, user has no idea
const [createItem] = useCreateItemMutation({
  onError: (error) => {
    console.error(error); // User sees nothing!
  },
});

错误状态组件模式

interface ErrorStateProps {
  error: Error;
  onRetry?: () => void;
  title?: string;
}

const ErrorState = ({ error, onRetry, title }: ErrorStateProps) => (
  <div className="error-state">
    <Icon name="exclamation-circle" />
    <h3>{title ?? 'Something went wrong'}</h3>
    <p>{error.message}</p>
    {onRetry && (
      <Button onClick={onRetry}>Try Again</Button>
    )}
  </div>
);

按钮状态模式

按钮加载状态

<Button
  onClick={handleSubmit}
  isLoading={isSubmitting}
  disabled={!isValid || isSubmitting}
>
  Submit
</Button>

操作期间禁用

关键：在异步操作期间始终禁用触发器。

// CORRECT - Button disabled while loading
<Button
  disabled={isSubmitting}
  isLoading={isSubmitting}
  onClick={handleSubmit}
>
  Submit
</Button>

// WRONG - User can tap multiple times
<Button onClick={handleSubmit}>
  {isSubmitting ? 'Submitting...' : 'Submit'}
</Button>

空状态

空状态要求

每个列表/集合都必须有空状态：

// WRONG - No empty state
return <FlatList data={items} />;

// CORRECT - Explicit empty state
return (
  <FlatList
    data={items}
    ListEmptyComponent={<EmptyState />}
  />
);

上下文空状态

// Search with no results
<EmptyState
  icon="search"
  title="No results found"
  description="Try different search terms"
/>

// List with no items yet
<EmptyState
  icon="plus-circle"
  title="No items yet"
  description="Create your first item"
  action={{ label: 'Create Item', onClick: handleCreate }}
/>

表单提交模式

const MyForm = () => {
  const [submit, { loading }] = useSubmitMutation({
    onCompleted: handleSuccess,
    onError: handleError,
  });

  const handleSubmit = async () => {
    if (!isValid) {
      toast.error({ title: 'Please fix errors' });
      return;
    }
    await submit({ variables: { input: values } });
  };

  return (
    <form>
      <Input
        value={values.name}
        onChange={handleChange('name')}
        error={touched.name ? errors.name : undefined}
      />
      <Button
        type="submit"
        onClick={handleSubmit}
        disabled={!isValid || loading}
        isLoading={loading}
      >
        Submit
      </Button>
    </form>
  );
};

反模式

加载状态

// WRONG - Spinner when data exists (causes flash)
if (loading) return <Spinner />;

// CORRECT - Only show loading without data
if (loading && !data) return <Spinner />;

错误处理

// WRONG - Error swallowed
try {
  await mutation();
} catch (e) {
  console.log(e); // User has no idea!
}

// CORRECT - Error surfaced
onError: (error) => {
  console.error('operation failed:', error);
  toast.error({ title: 'Operation failed' });
}

按钮状态

// WRONG - Button not disabled during submission
<Button onClick={submit}>Submit</Button>

// CORRECT - Disabled and shows loading
<Button onClick={submit} disabled={loading} isLoading={loading}>
  Submit
</Button>

检查清单

在完成任何 UI 组件之前：

UI 状态：

• 错误状态已处理并展示给用户
• 仅当不存在数据时才显示加载状态
• 为集合提供空状态
• 在异步操作期间禁用按钮
• 按钮在适当时显示加载指示器

数据与变更：

• 变更具有 onError 处理程序
• 所有用户操作都有反馈（toast/视觉）

与其他技能的集成

• graphql-schema：使用带有恰当错误处理的变更模式
• testing-patterns：测试所有 UI 状态（加载、错误、空、成功）
• formik-patterns：应用表单提交模式