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    <title>React · 仁才德</title>
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      <title>Zustand vs React Query（TanStack Query）vs AsyncStorage：状态该放在哪里</title>
      <link>https://jared.lynskey.co.nz/zh-cn/posts/2026/2026-05-05-zustand-vs-react-query/</link>
      <guid isPermaLink="true">https://jared.lynskey.co.nz/zh-cn/posts/2026/2026-05-05-zustand-vs-react-query/</guid>
      <pubDate>Tue, 05 May 2026 00:00:00 +0000</pubDate>
      <dc:creator>Jared Lynskey</dc:creator>
      <category>React</category>
      <category>React Native</category>
      <category>Zustand</category>
      <category>React Query</category>
      <category>TanStack Query</category>
      <category>AsyncStorage</category>
      <category>State Management</category>
      <category>Mobile Development</category>
      <category>Web Development</category>
      <description>Zustand 和 React Query 不是二选一：React Query（TanStack Query）缓存服务器状态，Zustand 管客户端状态，AsyncStorage 保存必须扛过重启的数据。我在 React 和 React Native 里怎么在三者之间划分状态，Zustand 和 React Query 怎么一起用，以及三者怎么组合出真正能用的离线模式。</description>
      <content:encoded><![CDATA[<p>Zustand 和 React Query 并不互相竞争，所以 &ldquo;Zustand 还是 React Query&rdquo; 这个问题，真正的答案通常是：两个都要。React Query（现在以 TanStack Query 的名字发布）管的是服务器状态，也就是归服务器所有的数据，由它负责拉取、缓存、去重，并在数据过期时重新拉取。Zustand 管的是客户端状态，只有你的应用自己知道的东西，比如当前打开的是哪个标签页、填了一半的表单里写了什么。大多数应用两个一起用；到了 React Native 里，AsyncStorage 是第三块，负责所有必须扛过重启的数据。这篇文章剩下的部分讲我把这几条线画在哪里（附代码），以及三者怎么合起来，做出一个离线也能用的应用。</p>
<p>我正在做的报价 App 有一条硬性要求：没信号也得能用。报价都是上门时在现场做的，而现场经常是毛坯房或者地下室，信号根本靠不住。正是这条约束，逼着我认真回答一个大多数 React 项目都含糊对付的问题：每种状态到底该放在哪里？</p>
<p>最常见的翻车方式，是把所有东西塞进同一个 store。API 缓存、用户偏好、表单状态、认证令牌，全搅在同一个 Redux 大泥球里。可这些状态的性质和生命周期各不相同，各有各的合适工具。Zustand、React Query、AsyncStorage 每个都恰好把一个问题解决得很好。边界画清楚了，架构基本就自己理顺了。</p>

<h2 class="relative group">状态分三种
    <div id="状态分三种" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%8a%b6%e6%80%81%e5%88%86%e4%b8%89%e7%a7%8d" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>聊库之前，先弄清楚自己到底在管理什么。</p>
<p>客户端状态只存在于应用运行时：UI 开关、选中的标签页、表单输入、弹窗开没开。上游没有谁拥有它，进程一结束它就没了。</p>
<p>服务器状态不一样。它的主人是服务器，应用手里只有一份本地副本。用户资料、商品列表、通知、动态流。你的副本会过期，需要重新拉取，而且此刻别的客户端可能正看着另一个版本。</p>
<p>持久化状态是那些必须扛过重启的数据：认证令牌、引导完成标记、缓存的偏好、离线数据。它存在设备本身上。</p>
<p>大多数应用三种都有。大多数烂摊子，都是拿一个工具硬管三种状态造成的。</p>

<h2 class="relative group">Zustand：管客户端状态
    <div id="zustand管客户端状态" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#zustand%e7%ae%a1%e5%ae%a2%e6%88%b7%e7%ab%af%e7%8a%b6%e6%80%81" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>Zustand 是个没什么仪式感的小状态库。没有 provider，没有模板代码，没有一层套一层的 context。建个 store，组件里直接用，要学的基本就这些。</p>
<p>它适合的场景：多个组件共享同一份 UI 状态（侧边栏开关、当前筛选条件、选中的项目）；不来自 API 的应用级状态（主题、语言、启动时读的功能开关）；以及真正的客户端逻辑，比如购物车计算或多步表单向导。凡是需要同步、可预测地更新的，基本都归它。</p>
<p>一个基础的 store：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">create</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;zustand&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">interface</span> <span class="nx">AppState</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">theme</span><span class="o">:</span> <span class="s1">&#39;light&#39;</span> <span class="o">|</span> <span class="s1">&#39;dark&#39;</span>
</span></span><span class="line"><span class="cl">  <span class="nx">sidebarOpen</span>: <span class="kt">boolean</span>
</span></span><span class="line"><span class="cl">  <span class="nx">selectedFilters</span>: <span class="kt">string</span><span class="p">[]</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setTheme</span><span class="o">:</span> <span class="p">(</span><span class="nx">theme</span><span class="o">:</span> <span class="s1">&#39;light&#39;</span> <span class="o">|</span> <span class="s1">&#39;dark&#39;</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="k">void</span>
</span></span><span class="line"><span class="cl">  <span class="nx">toggleSidebar</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="k">void</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setFilters</span><span class="o">:</span> <span class="p">(</span><span class="nx">filters</span>: <span class="kt">string</span><span class="p">[])</span> <span class="o">=&gt;</span> <span class="k">void</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">useAppStore</span> <span class="o">=</span> <span class="nx">create</span><span class="p">&lt;</span><span class="nt">AppState</span><span class="p">&gt;((</span><span class="kr">set</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">theme</span><span class="o">:</span> <span class="s1">&#39;light&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">sidebarOpen</span>: <span class="kt">false</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">selectedFilters</span><span class="o">:</span> <span class="p">[],</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setTheme</span><span class="o">:</span> <span class="p">(</span><span class="nx">theme</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="kr">set</span><span class="p">({</span> <span class="nx">theme</span> <span class="p">}),</span>
</span></span><span class="line"><span class="cl">  <span class="nx">toggleSidebar</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="kr">set</span><span class="p">((</span><span class="nx">state</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">({</span> <span class="nx">sidebarOpen</span><span class="o">:</span> <span class="o">!</span><span class="nx">state</span><span class="p">.</span><span class="nx">sidebarOpen</span> <span class="p">})),</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setFilters</span><span class="o">:</span> <span class="p">(</span><span class="nx">filters</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="kr">set</span><span class="p">({</span> <span class="nx">selectedFilters</span>: <span class="kt">filters</span> <span class="p">}),</span>
</span></span><span class="line"><span class="cl"><span class="p">}))</span></span></span></code></pre></div></div>
<p>组件里这样用：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-tsx" data-lang="tsx"><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">Sidebar() {</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="p">{</span> <span class="nx">sidebarOpen</span><span class="p">,</span> <span class="nx">toggleSidebar</span> <span class="p">}</span> <span class="o">=</span> <span class="nx">useAppStore</span><span class="p">()</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nx">sidebarOpen</span><span class="p">)</span> <span class="k">return</span> <span class="kc">null</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;</span><span class="nt">div</span> <span class="na">className</span><span class="o">=</span><span class="s">&#34;sidebar&#34;</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;</span><span class="nt">button</span> <span class="na">onClick</span><span class="o">=</span><span class="p">{</span><span class="nx">toggleSidebar</span><span class="p">}&gt;</span><span class="nx">Close</span><span class="p">&lt;/</span><span class="nt">button</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">{</span><span class="cm">/* sidebar content */</span><span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">  <span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>

<h3 class="relative group">我不往 Zustand 里放的东西
    <div id="我不往-zustand-里放的东西" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e6%88%91%e4%b8%8d%e5%be%80-zustand-%e9%87%8c%e6%94%be%e7%9a%84%e4%b8%9c%e8%a5%bf" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>首先是 API 响应。我见过这样的项目：每次 API 调用都写进 Zustand store，组件不查询接口，改从 store 里读。结局就是自己手搓缓存失效、加载状态、错误处理、重新拉取和分页，而这些恰恰是 React Query 白送的。</p>
<p>其次是需要扛过重启的数据。Zustand 的状态在内存里，应用一关就没了。persist 中间件可以搭桥到 AsyncStorage（后面会讲），但那应该是想清楚之后的决定，而不是顺手为之。</p>

<h2 class="relative group">React Query：管服务器状态
    <div id="react-query管服务器状态" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#react-query%e7%ae%a1%e6%9c%8d%e5%8a%a1%e5%99%a8%e7%8a%b6%e6%80%81" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>React Query（现在叫 TanStack Query）管理远程数据的整个生命周期：拉取、缓存、同步、更新、垃圾回收。关键的观念转变，是把服务器数据当成一份要保持新鲜的缓存，而不是你拥有的状态。数据的主人是服务器，你只是暂存了一份副本。</p>
<p>只要是 API 来的数据，我一律交给它。多个组件用同一个接口的数据（请求会自动去重）、分页和无限滚动、用户回到应用时需要后台刷新的数据、先改 UI 被服务器拒绝再回滚的乐观更新，全在它的射程之内。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">useQuery</span><span class="p">,</span> <span class="nx">useMutation</span><span class="p">,</span> <span class="nx">useQueryClient</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">useUser</span><span class="p">(</span><span class="nx">userId</span>: <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">useQuery</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queryKey</span><span class="o">:</span> <span class="p">[</span><span class="s1">&#39;user&#39;</span><span class="p">,</span> <span class="nx">userId</span><span class="p">],</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queryFn</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="nx">fetch</span><span class="p">(</span><span class="sb">`/api/users/</span><span class="si">${</span><span class="nx">userId</span><span class="si">}</span><span class="sb">`</span><span class="p">).</span><span class="nx">then</span><span class="p">(</span><span class="nx">res</span> <span class="o">=&gt;</span> <span class="nx">res</span><span class="p">.</span><span class="nx">json</span><span class="p">()),</span>
</span></span><span class="line"><span class="cl">    <span class="nx">staleTime</span>: <span class="kt">5</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">1000</span><span class="p">,</span> <span class="c1">// 5 分钟内视为新鲜
</span></span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">useUpdateUser() {</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">queryClient</span> <span class="o">=</span> <span class="nx">useQueryClient</span><span class="p">()</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">useMutation</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">    <span class="nx">mutationFn</span><span class="o">:</span> <span class="p">(</span><span class="nx">data</span><span class="o">:</span> <span class="p">{</span> <span class="nx">id</span>: <span class="kt">string</span><span class="p">;</span> <span class="nx">name</span>: <span class="kt">string</span> <span class="p">})</span> <span class="o">=&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="nx">fetch</span><span class="p">(</span><span class="sb">`/api/users/</span><span class="si">${</span><span class="nx">data</span><span class="p">.</span><span class="nx">id</span><span class="si">}</span><span class="sb">`</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">method</span><span class="o">:</span> <span class="s1">&#39;PATCH&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">body</span>: <span class="kt">JSON.stringify</span><span class="p">(</span><span class="nx">data</span><span class="p">),</span>
</span></span><span class="line"><span class="cl">      <span class="p">}),</span>
</span></span><span class="line"><span class="cl">    <span class="nx">onSuccess</span><span class="o">:</span> <span class="p">(</span><span class="nx">_</span><span class="p">,</span> <span class="nx">variables</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">queryClient</span><span class="p">.</span><span class="nx">invalidateQueries</span><span class="p">({</span> <span class="nx">queryKey</span><span class="o">:</span> <span class="p">[</span><span class="s1">&#39;user&#39;</span><span class="p">,</span> <span class="nx">variables</span><span class="p">.</span><span class="nx">id</span><span class="p">]</span> <span class="p">})</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>
<p>组件里：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-tsx" data-lang="tsx"><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">UserProfile</span><span class="p">({</span> <span class="nx">userId</span> <span class="p">}</span><span class="o">:</span> <span class="p">{</span> <span class="nx">userId</span>: <span class="kt">string</span> <span class="p">})</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="p">{</span> <span class="nx">data</span>: <span class="kt">user</span><span class="p">,</span> <span class="nx">isLoading</span><span class="p">,</span> <span class="nx">error</span> <span class="p">}</span> <span class="o">=</span> <span class="nx">useUser</span><span class="p">(</span><span class="nx">userId</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">updateUser</span> <span class="o">=</span> <span class="nx">useUpdateUser</span><span class="p">()</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">isLoading</span><span class="p">)</span> <span class="k">return</span> <span class="p">&lt;</span><span class="nt">Spinner</span> <span class="p">/&gt;</span>
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">error</span><span class="p">)</span> <span class="k">return</span> <span class="p">&lt;</span><span class="nt">ErrorMessage</span> <span class="na">error</span><span class="o">=</span><span class="p">{</span><span class="nx">error</span><span class="p">}</span> <span class="p">/&gt;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;</span><span class="nt">div</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;</span><span class="nt">h1</span><span class="p">&gt;{</span><span class="nx">user</span><span class="p">.</span><span class="nx">name</span><span class="p">}&lt;/</span><span class="nt">h1</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;</span><span class="nt">button</span>
</span></span><span class="line"><span class="cl">        <span class="na">onClick</span><span class="o">=</span><span class="p">{()</span> <span class="o">=&gt;</span> <span class="nx">updateUser</span><span class="p">.</span><span class="nx">mutate</span><span class="p">({</span> <span class="nx">id</span>: <span class="kt">userId</span><span class="p">,</span> <span class="nx">name</span><span class="o">:</span> <span class="s1">&#39;New Name&#39;</span> <span class="p">})}</span>
</span></span><span class="line"><span class="cl">        <span class="na">disabled</span><span class="o">=</span><span class="p">{</span><span class="nx">updateUser</span><span class="p">.</span><span class="nx">isPending</span><span class="p">}</span>
</span></span><span class="line"><span class="cl">      <span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">        <span class="nx">Update</span> <span class="nx">Name</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;/</span><span class="nt">button</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">  <span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>

<h3 class="relative group">不用自己写的那些东西
    <div id="不用自己写的那些东西" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e4%b8%8d%e7%94%a8%e8%87%aa%e5%b7%b1%e5%86%99%e7%9a%84%e9%82%a3%e4%ba%9b%e4%b8%9c%e8%a5%bf" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>我坚持把服务器数据放这儿，就是因为白送的机制实在太多。五个组件请求同一个用户，网络请求只发一次。窗口重新聚焦或网络重连时自动重新拉取。过期缓存自动垃圾回收。每个查询都带着 <code>isLoading</code>、<code>isError</code>、<code>data</code>，加载和错误 UI 不用每次现做。失败的请求按指数退避自动重试。带回滚的乐观更新是内置模式，不用花一下午自己接管道。</p>

<h3 class="relative group">它不适合干什么
    <div id="它不适合干什么" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e5%ae%83%e4%b8%8d%e9%80%82%e5%90%88%e5%b9%b2%e4%bb%80%e4%b9%88" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>纯客户端状态。数据压根不经过服务器的话，React Query 只会平添仪式感。弹窗的开关状态不需要缓存失效，也不需要重新拉取间隔。</p>
<p>它也不是持久化层。缓存在内存里，重启就清空、全部重拉。缓存可以持久化（React Native 上也确实应该做，见下面的离线部分），但数据的真实来源永远是服务器。</p>

<h2 class="relative group">AsyncStorage：管扛过重启的数据
    <div id="asyncstorage管扛过重启的数据" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#asyncstorage%e7%ae%a1%e6%89%9b%e8%bf%87%e9%87%8d%e5%90%af%e7%9a%84%e6%95%b0%e6%8d%ae" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>AsyncStorage 是 React Native 的键值存储。Web 上对应的是 <code>localStorage</code>（同步）或 <code>IndexedDB</code>（异步、能力更强）。思路都一样：写到设备上，让数据活得比进程久。</p>

<h3 class="relative group">各平台底下是什么
    <div id="各平台底下是什么" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e5%90%84%e5%b9%b3%e5%8f%b0%e5%ba%95%e4%b8%8b%e6%98%af%e4%bb%80%e4%b9%88" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>用 <code>@react-native-async-storage/async-storage</code> 的话 API 只有一套，但底下的实现每个平台差别不小。</p>
<p>Android 上是走 <code>RKStorage</code> 的 SQLite，数据库放在应用内部存储目录里。快、可靠、有沙盒隔离，别的应用碰不到。不过要留意下表里的默认容量上限。</p>
<p>iOS 上，小值走 <code>NSUserDefaults</code>，大值走序列化文件，同样被沙盒在应用容器里。Apple 没给 <code>NSUserDefaults</code> 定硬上限，但单个值控制在几百 KB 以内是共识。真有那么大的值，八成该直接上 WatermelonDB 或 Realm 这种正经数据库了。</p>
<p>Web 上（React Native Web / Expo Web）会退回 <code>localStorage</code>，上限看浏览器，大概 5-10 MB。纯 Web 的 React 应用直接用 <code>localStorage</code> 就行，数据大了就通过 <code>idb-keyval</code> 这类封装用 <code>IndexedDB</code>。</p>
<table>
	<thead>
			<tr>
					<th>平台</th>
					<th>底层实现</th>
					<th>容量上限</th>
					<th>存储位置</th>
			</tr>
	</thead>
	<tbody>
			<tr>
					<td>Android</td>
					<td>SQLite (RKStorage)</td>
					<td>默认约 6 MB（可配置）</td>
					<td>应用内部存储</td>
			</tr>
			<tr>
					<td>iOS</td>
					<td>NSUserDefaults / 文件</td>
					<td>无硬上限（单个值尽量小）</td>
					<td>应用沙盒容器</td>
			</tr>
			<tr>
					<td>Web</td>
					<td>localStorage</td>
					<td>约 5-10 MB（因浏览器而异）</td>
					<td>浏览器按源（origin）隔离的存储</td>
			</tr>
	</tbody>
</table>

<h3 class="relative group">我放进去的东西
    <div id="我放进去的东西" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e6%88%91%e6%94%be%e8%bf%9b%e5%8e%bb%e7%9a%84%e4%b8%9c%e8%a5%bf" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>认证令牌和会话数据、需要留下来的用户偏好（语言、主题、通知设置）、引导完成标记、离线用的缓存数据。一句话概括：需要扛过重启的小型键值数据，这个类别就这么大。</p>
<p>API 大概是存储方案里最朴素的样子：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">AsyncStorage</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-async-storage/async-storage&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 存储一个值
</span></span></span><span class="line"><span class="cl"><span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;auth_token&#39;</span><span class="p">,</span> <span class="nx">token</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 读取一个值
</span></span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">token</span> <span class="o">=</span> <span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;auth_token&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 存储一个对象（需要序列化）
</span></span></span><span class="line"><span class="cl"><span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;user_preferences&#39;</span><span class="p">,</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">stringify</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">theme</span><span class="o">:</span> <span class="s1">&#39;dark&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">language</span><span class="o">:</span> <span class="s1">&#39;en&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">notifications</span>: <span class="kt">true</span><span class="p">,</span>
</span></span><span class="line"><span class="cl"><span class="p">}))</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 读取一个对象
</span></span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">prefs</span> <span class="o">=</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">parse</span><span class="p">(</span><span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;user_preferences&#39;</span><span class="p">)</span> <span class="o">??</span> <span class="s1">&#39;{}&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 删除一个值
</span></span></span><span class="line"><span class="cl"><span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">removeItem</span><span class="p">(</span><span class="s1">&#39;auth_token&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 清空所有数据（慎用）
</span></span></span><span class="line"><span class="cl"><span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">clear</span><span class="p">()</span></span></span></code></pre></div></div>

<h3 class="relative group">Web 上怎么办
    <div id="web-上怎么办" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#web-%e4%b8%8a%e6%80%8e%e4%b9%88%e5%8a%9e" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>纯 Web 的 React 应用完全不需要 AsyncStorage。简单键值对用 <code>localStorage</code>：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="c1">// 同步的 - 会阻塞主线程，但对于小数据没问题
</span></span></span><span class="line"><span class="cl"><span class="nx">localStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;theme&#39;</span><span class="p">,</span> <span class="s1">&#39;dark&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">theme</span> <span class="o">=</span> <span class="nx">localStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;theme&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 结构化数据
</span></span></span><span class="line"><span class="cl"><span class="nx">localStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;user&#39;</span><span class="p">,</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">stringify</span><span class="p">({</span> <span class="nx">name</span><span class="o">:</span> <span class="s1">&#39;Jared&#39;</span><span class="p">,</span> <span class="nx">role</span><span class="o">:</span> <span class="s1">&#39;admin&#39;</span> <span class="p">}))</span>
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">user</span> <span class="o">=</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">parse</span><span class="p">(</span><span class="nx">localStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;user&#39;</span><span class="p">)</span> <span class="o">??</span> <span class="s1">&#39;{}&#39;</span><span class="p">)</span></span></span></code></pre></div></div>
<p>数据集大了用 <code>IndexedDB</code>：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="kr">get</span><span class="p">,</span> <span class="kr">set</span><span class="p">,</span> <span class="nx">del</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;idb-keyval&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="k">await</span> <span class="kr">set</span><span class="p">(</span><span class="s1">&#39;large-dataset&#39;</span><span class="p">,</span> <span class="nx">hugeArray</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">data</span> <span class="o">=</span> <span class="k">await</span> <span class="kr">get</span><span class="p">(</span><span class="s1">&#39;large-dataset&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="k">await</span> <span class="nx">del</span><span class="p">(</span><span class="s1">&#39;large-dataset&#39;</span><span class="p">)</span></span></span></code></pre></div></div>

<h3 class="relative group">它不适合干什么
    <div id="它不适合干什么-1" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e5%ae%83%e4%b8%8d%e9%80%82%e5%90%88%e5%b9%b2%e4%bb%80%e4%b9%88-1" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>它是键值存储，不是数据库。关系型数据、几千上万条的数组、需要索引和查询的东西，归 SQLite（走 <code>expo-sqlite</code>）、WatermelonDB 或 Realm 管。</p>
<p>它也不是安全存储。设备一旦被 root 或越狱，AsyncStorage 里的内容就是明着放的。敏感令牌请放 <code>expo-secure-store</code> 或 <code>react-native-keychain</code>。</p>

<h2 class="relative group">三个怎么搭配着用
    <div id="三个怎么搭配着用" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e4%b8%89%e4%b8%aa%e6%80%8e%e4%b9%88%e6%90%ad%e9%85%8d%e7%9d%80%e7%94%a8" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>真实的应用里三个是一起上的。几个我常用的搭配。</p>

<h3 class="relative group">认证流程
    <div id="认证流程" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e8%ae%a4%e8%af%81%e6%b5%81%e7%a8%8b" aria-label="锚点">#</a>
    </span>
    
</h3>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="c1">// 1. AsyncStorage: 持久化认证令牌
</span></span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">AsyncStorage</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-async-storage/async-storage&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">async</span> <span class="kd">function</span> <span class="nx">saveToken</span><span class="p">(</span><span class="nx">token</span>: <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;auth_token&#39;</span><span class="p">,</span> <span class="nx">token</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">async</span> <span class="kd">function</span> <span class="nx">getToken</span><span class="p">()</span><span class="o">:</span> <span class="nx">Promise</span><span class="p">&lt;</span><span class="nt">string</span> <span class="err">|</span> <span class="na">null</span><span class="p">&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;auth_token&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 2. Zustand: 在内存中跟踪认证状态
</span></span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">create</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;zustand&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">interface</span> <span class="nx">AuthState</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">isAuthenticated</span>: <span class="kt">boolean</span>
</span></span><span class="line"><span class="cl">  <span class="nx">token</span>: <span class="kt">string</span> <span class="o">|</span> <span class="kc">null</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setAuth</span><span class="o">:</span> <span class="p">(</span><span class="nx">token</span>: <span class="kt">string</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="k">void</span>
</span></span><span class="line"><span class="cl">  <span class="nx">clearAuth</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="k">void</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">useAuthStore</span> <span class="o">=</span> <span class="nx">create</span><span class="p">&lt;</span><span class="nt">AuthState</span><span class="p">&gt;((</span><span class="kr">set</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">isAuthenticated</span>: <span class="kt">false</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">token</span>: <span class="kt">null</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setAuth</span><span class="o">:</span> <span class="p">(</span><span class="nx">token</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="kr">set</span><span class="p">({</span> <span class="nx">isAuthenticated</span>: <span class="kt">true</span><span class="p">,</span> <span class="nx">token</span> <span class="p">}),</span>
</span></span><span class="line"><span class="cl">  <span class="nx">clearAuth</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="kr">set</span><span class="p">({</span> <span class="nx">isAuthenticated</span>: <span class="kt">false</span><span class="p">,</span> <span class="nx">token</span>: <span class="kt">null</span> <span class="p">}),</span>
</span></span><span class="line"><span class="cl"><span class="p">}))</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 3. React Query: 使用令牌获取用户资料
</span></span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">useCurrentUser() {</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">token</span> <span class="o">=</span> <span class="nx">useAuthStore</span><span class="p">((</span><span class="nx">s</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="nx">s</span><span class="p">.</span><span class="nx">token</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">useQuery</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queryKey</span><span class="o">:</span> <span class="p">[</span><span class="s1">&#39;currentUser&#39;</span><span class="p">],</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queryFn</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="nx">fetch</span><span class="p">(</span><span class="s1">&#39;/api/me&#39;</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">headers</span><span class="o">:</span> <span class="p">{</span> <span class="nx">Authorization</span><span class="o">:</span> <span class="sb">`Bearer </span><span class="si">${</span><span class="nx">token</span><span class="si">}</span><span class="sb">`</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">      <span class="p">}).</span><span class="nx">then</span><span class="p">(</span><span class="nx">res</span> <span class="o">=&gt;</span> <span class="nx">res</span><span class="p">.</span><span class="nx">json</span><span class="p">()),</span>
</span></span><span class="line"><span class="cl">    <span class="nx">enabled</span><span class="o">:</span> <span class="o">!!</span><span class="nx">token</span><span class="p">,</span> <span class="c1">// 只在有令牌时才发请求
</span></span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>
<p>启动时：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="c1">// 应用初始化
</span></span></span><span class="line"><span class="cl"><span class="kr">async</span> <span class="kd">function</span> <span class="nx">initializeApp() {</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">token</span> <span class="o">=</span> <span class="k">await</span> <span class="nx">getToken</span><span class="p">()</span> <span class="c1">// 从 AsyncStorage 读取
</span></span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">token</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">useAuthStore</span><span class="p">.</span><span class="nx">getState</span><span class="p">().</span><span class="nx">setAuth</span><span class="p">(</span><span class="nx">token</span><span class="p">)</span> <span class="c1">// 放入 Zustand 以便快速访问
</span></span></span><span class="line"><span class="cl">    <span class="c1">// React Query 会自动拉取用户资料
</span></span></span><span class="line"><span class="cl">  <span class="p">}</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>
<p>AsyncStorage 负责让令牌扛过重启，Zustand 让它在任何地方都能低成本读到，React Query 则在令牌一就位时去拉用户资料。每个工具只干自己最擅长的那件事。</p>

<h3 class="relative group">重启后还在的主题设置
    <div id="重启后还在的主题设置" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e9%87%8d%e5%90%af%e5%90%8e%e8%bf%98%e5%9c%a8%e7%9a%84%e4%b8%bb%e9%a2%98%e8%ae%be%e7%bd%ae" aria-label="锚点">#</a>
    </span>
    
</h3>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">create</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;zustand&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">persist</span><span class="p">,</span> <span class="nx">createJSONStorage</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;zustand/middleware&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">AsyncStorage</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-async-storage/async-storage&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// Zustand 的持久化中间件在两者之间搭建了桥梁
</span></span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">useThemeStore</span> <span class="o">=</span> <span class="nx">create</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">  <span class="nx">persist</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="p">(</span><span class="kr">set</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">({</span>
</span></span><span class="line"><span class="cl">      <span class="nx">theme</span><span class="o">:</span> <span class="s1">&#39;light&#39;</span> <span class="kr">as</span> <span class="s1">&#39;light&#39;</span> <span class="o">|</span> <span class="s1">&#39;dark&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">      <span class="nx">toggleTheme</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span>
</span></span><span class="line"><span class="cl">        <span class="kr">set</span><span class="p">((</span><span class="nx">state</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">({</span>
</span></span><span class="line"><span class="cl">          <span class="nx">theme</span>: <span class="kt">state.theme</span> <span class="o">===</span> <span class="s1">&#39;light&#39;</span> <span class="o">?</span> <span class="s1">&#39;dark&#39;</span> <span class="o">:</span> <span class="s1">&#39;light&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="p">})),</span>
</span></span><span class="line"><span class="cl">    <span class="p">}),</span>
</span></span><span class="line"><span class="cl">    <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">name</span><span class="o">:</span> <span class="s1">&#39;theme-storage&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">      <span class="nx">storage</span>: <span class="kt">createJSONStorage</span><span class="p">(()</span> <span class="o">=&gt;</span> <span class="nx">AsyncStorage</span><span class="p">),</span> <span class="c1">// React Native
</span></span></span><span class="line"><span class="cl">      <span class="c1">// storage: createJSONStorage(() =&gt; localStorage), // Web
</span></span></span><span class="line"><span class="cl">    <span class="p">}</span>
</span></span><span class="line"><span class="cl">  <span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">)</span></span></span></code></pre></div></div>
<p>运行时状态归 Zustand 管，persist 中间件在背后同步到 AsyncStorage（Web 上是 localStorage）。组件既不知道也不需要知道持久化层的存在。</p>

<h3 class="relative group">离线优先的读取
    <div id="离线优先的读取" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%a6%bb%e7%ba%bf%e4%bc%98%e5%85%88%e7%9a%84%e8%af%bb%e5%8f%96" aria-label="锚点">#</a>
    </span>
    
</h3>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">useQuery</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">AsyncStorage</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-async-storage/async-storage&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">useProducts() {</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">useQuery</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queryKey</span><span class="o">:</span> <span class="p">[</span><span class="s1">&#39;products&#39;</span><span class="p">],</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queryFn</span>: <span class="kt">async</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">try</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="kr">const</span> <span class="nx">res</span> <span class="o">=</span> <span class="k">await</span> <span class="nx">fetch</span><span class="p">(</span><span class="s1">&#39;/api/products&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="kr">const</span> <span class="nx">data</span> <span class="o">=</span> <span class="k">await</span> <span class="nx">res</span><span class="p">.</span><span class="nx">json</span><span class="p">()</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="c1">// 缓存到 AsyncStorage 以供离线使用
</span></span></span><span class="line"><span class="cl">        <span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;cached_products&#39;</span><span class="p">,</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">stringify</span><span class="p">(</span><span class="nx">data</span><span class="p">))</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nx">data</span>
</span></span><span class="line"><span class="cl">      <span class="p">}</span> <span class="k">catch</span> <span class="p">(</span><span class="nx">error</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// 网络请求失败 - 尝试使用缓存数据
</span></span></span><span class="line"><span class="cl">        <span class="kr">const</span> <span class="nx">cached</span> <span class="o">=</span> <span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;cached_products&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="nx">cached</span><span class="p">)</span> <span class="k">return</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">parse</span><span class="p">(</span><span class="nx">cached</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">        <span class="k">throw</span> <span class="nx">error</span>
</span></span><span class="line"><span class="cl">      <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">    <span class="nx">staleTime</span>: <span class="kt">10</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">1000</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>
<p>拉取和内存缓存归 React Query，断网时的兜底归 AsyncStorage，分工就这么简单。</p>

<h2 class="relative group">离线模式，一步一步来
    <div id="离线模式一步一步来" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%a6%bb%e7%ba%bf%e6%a8%a1%e5%bc%8f%e4%b8%80%e6%ad%a5%e4%b8%80%e6%ad%a5%e6%9d%a5" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>这部分才是我真正关心的。通常的说法是用户会在地铁、电梯、飞机上打开应用，这没错。但我的情况更直接：报价就是在现场写的，而现场有没有信号全看运气。地下室里转圈的加载动画，意味着丢掉一单报价。</p>
<p>好消息是，就靠这三个库，不用上重型框架也能搭出相当扎实的离线方案。</p>

<h3 class="relative group">第一步：知道自己断网了
    <div id="第一步知道自己断网了" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ac%ac%e4%b8%80%e6%ad%a5%e7%9f%a5%e9%81%93%e8%87%aa%e5%b7%b1%e6%96%ad%e7%bd%91%e4%ba%86" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>设备得把网络状态告诉应用，应用得有个地方存这个答案。事件由 <code>@react-native-community/netinfo</code> 提供，再用一个小小的 Zustand store 让全应用都能读到。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">create</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;zustand&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">NetInfo</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-community/netinfo&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">interface</span> <span class="nx">NetworkState</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">isOnline</span>: <span class="kt">boolean</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setOnline</span><span class="o">:</span> <span class="p">(</span><span class="nx">online</span>: <span class="kt">boolean</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="k">void</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">useNetworkStore</span> <span class="o">=</span> <span class="nx">create</span><span class="p">&lt;</span><span class="nt">NetworkState</span><span class="p">&gt;((</span><span class="kr">set</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">isOnline</span>: <span class="kt">true</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">setOnline</span><span class="o">:</span> <span class="p">(</span><span class="nx">online</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="kr">set</span><span class="p">({</span> <span class="nx">isOnline</span>: <span class="kt">online</span> <span class="p">}),</span>
</span></span><span class="line"><span class="cl"><span class="p">}))</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 应用启动时订阅一次
</span></span></span><span class="line"><span class="cl"><span class="nx">NetInfo</span><span class="p">.</span><span class="nx">addEventListener</span><span class="p">((</span><span class="nx">state</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">useNetworkStore</span><span class="p">.</span><span class="nx">getState</span><span class="p">().</span><span class="nx">setOnline</span><span class="p">(</span><span class="nx">state</span><span class="p">.</span><span class="nx">isConnected</span> <span class="o">??</span> <span class="kc">false</span><span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span></span></span></code></pre></div></div>
<p>之后任何组件都能通过 <code>useNetworkStore((s) =&gt; s.isOnline)</code> 来显示离线横幅、禁用提交按钮，或者提示“联网后会自动同步”。</p>

<h3 class="relative group">第二步：把离线告诉 React Query
    <div id="第二步把离线告诉-react-query" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ac%ac%e4%ba%8c%e6%ad%a5%e6%8a%8a%e7%a6%bb%e7%ba%bf%e5%91%8a%e8%af%89-react-query" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>React Query 内置了 <code>networkMode</code>，控制断网时查询和变更的行为。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">QueryClient</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">queryClient</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">QueryClient</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">defaultOptions</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queries</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">networkMode</span><span class="o">:</span> <span class="s1">&#39;offlineFirst&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">      <span class="c1">// 先返回缓存数据，联网后在后台重新拉取
</span></span></span><span class="line"><span class="cl">      <span class="nx">staleTime</span>: <span class="kt">5</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">1000</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">      <span class="nx">gcTime</span>: <span class="kt">24</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">1000</span><span class="p">,</span> <span class="c1">// 缓存保留 24 小时
</span></span></span><span class="line"><span class="cl">      <span class="nx">retry</span><span class="o">:</span> <span class="p">(</span><span class="nx">failureCount</span><span class="p">,</span> <span class="nx">error</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="c1">// 离线时不要重试 - 反正也会失败
</span></span></span><span class="line"><span class="cl">        <span class="k">if</span> <span class="p">(</span><span class="o">!</span><span class="nx">useNetworkStore</span><span class="p">.</span><span class="nx">getState</span><span class="p">().</span><span class="nx">isOnline</span><span class="p">)</span> <span class="k">return</span> <span class="kc">false</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="nx">failureCount</span> <span class="o">&lt;</span> <span class="mi">3</span>
</span></span><span class="line"><span class="cl">      <span class="p">},</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">    <span class="nx">mutations</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">networkMode</span><span class="o">:</span> <span class="s1">&#39;offlineFirst&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">},</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span></span></span></code></pre></div></div>
<p>三种模式：</p>
<table>
	<thead>
			<tr>
					<th>模式</th>
					<th>行为</th>
			</tr>
	</thead>
	<tbody>
			<tr>
					<td><code>online</code>（默认）</td>
					<td>只在联网时发起查询，断网时暂停。</td>
			</tr>
			<tr>
					<td><code>always</code></td>
					<td>不管网络状态都发起查询，失败由你的 <code>queryFn</code> 处理。</td>
			</tr>
			<tr>
					<td><code>offlineFirst</code></td>
					<td>先发起一次查询（取缓存数据），之后暂停，等联网再重新拉取。</td>
			</tr>
	</tbody>
</table>
<p>大多数移动应用选 <code>offlineFirst</code> 就对了：缓存数据立刻出现，新数据等网络允许时再来。</p>

<h3 class="relative group">第三步：持久化查询缓存
    <div id="第三步持久化查询缓存" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ac%ac%e4%b8%89%e6%ad%a5%e6%8c%81%e4%b9%85%e5%8c%96%e6%9f%a5%e8%af%a2%e7%bc%93%e5%ad%98" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>默认缓存只在内存里，一重启就满屏转圈。要做离线模式，得把缓存持久化到 AsyncStorage：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">QueryClient</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">PersistQueryClientProvider</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query-persist-client&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">createAsyncStoragePersister</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/query-async-storage-persister&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">AsyncStorage</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-async-storage/async-storage&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">queryClient</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">QueryClient</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">defaultOptions</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">queries</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">gcTime</span>: <span class="kt">24</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">1000</span><span class="p">,</span> <span class="c1">// 24 小时 - 必须 &gt;= maxAge
</span></span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">},</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">asyncStoragePersister</span> <span class="o">=</span> <span class="nx">createAsyncStoragePersister</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">storage</span>: <span class="kt">AsyncStorage</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="nx">key</span><span class="o">:</span> <span class="s1">&#39;react-query-cache&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 在你的 App 组件中
</span></span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">App() {</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;</span><span class="nt">PersistQueryClientProvider</span>
</span></span><span class="line"><span class="cl">      <span class="na">client</span><span class="o">=</span><span class="p">{</span><span class="nx">queryClient</span><span class="p">}</span>
</span></span><span class="line"><span class="cl">      <span class="na">persistOptions</span><span class="o">=</span><span class="p">{{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">persister</span>: <span class="kt">asyncStoragePersister</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">maxAge</span>: <span class="kt">24</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">60</span> <span class="o">*</span> <span class="mi">1000</span><span class="p">,</span> <span class="c1">// 不恢复超过 24 小时的数据
</span></span></span><span class="line"><span class="cl">        <span class="nx">dehydrateOptions</span><span class="o">:</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">          <span class="nx">shouldDehydrateQuery</span><span class="o">:</span> <span class="p">(</span><span class="nx">query</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">            <span class="c1">// 只持久化成功的查询
</span></span></span><span class="line"><span class="cl">            <span class="k">return</span> <span class="nx">query</span><span class="p">.</span><span class="nx">state</span><span class="p">.</span><span class="nx">status</span> <span class="o">===</span> <span class="s1">&#39;success&#39;</span>
</span></span><span class="line"><span class="cl">          <span class="p">},</span>
</span></span><span class="line"><span class="cl">        <span class="p">},</span>
</span></span><span class="line"><span class="cl">      <span class="p">}}</span>
</span></span><span class="line"><span class="cl">    <span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;</span><span class="nt">YourApp</span> <span class="p">/&gt;</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;/</span><span class="nt">PersistQueryClientProvider</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">  <span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>
<p>这样在没信号的地方打开应用，看到的是上次拉取的数据而不是白屏；网络一恢复，React Query 就在后台悄悄重拉。</p>

<h3 class="relative group">第四步：离线时把写操作排进队列
    <div id="第四步离线时把写操作排进队列" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ac%ac%e5%9b%9b%e6%ad%a5%e7%a6%bb%e7%ba%bf%e6%97%b6%e6%8a%8a%e5%86%99%e6%93%8d%e4%bd%9c%e6%8e%92%e8%bf%9b%e9%98%9f%e5%88%97" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>读是容易的那一半。有意思的是写：用户断网时发了评论、提交了订单、改了资料，这些变更得排队存好，等网络回来再重放。</p>
<p>React Query 的答案是 <code>useMutation</code> 加上 <code>onMutate</code> 里的乐观更新：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">useMutation</span><span class="p">,</span> <span class="nx">useQueryClient</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">AsyncStorage</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-async-storage/async-storage&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kr">interface</span> <span class="nx">Comment</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">id</span>: <span class="kt">string</span>
</span></span><span class="line"><span class="cl">  <span class="nx">text</span>: <span class="kt">string</span>
</span></span><span class="line"><span class="cl">  <span class="nx">postId</span>: <span class="kt">string</span>
</span></span><span class="line"><span class="cl">  <span class="nx">createdAt</span>: <span class="kt">string</span>
</span></span><span class="line"><span class="cl">  <span class="nx">pending?</span>: <span class="kt">boolean</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">useAddComment</span><span class="p">(</span><span class="nx">postId</span>: <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">queryClient</span> <span class="o">=</span> <span class="nx">useQueryClient</span><span class="p">()</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">useMutation</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">    <span class="nx">mutationFn</span>: <span class="kt">async</span> <span class="p">(</span><span class="nx">text</span>: <span class="kt">string</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">res</span> <span class="o">=</span> <span class="k">await</span> <span class="nx">fetch</span><span class="p">(</span><span class="sb">`/api/posts/</span><span class="si">${</span><span class="nx">postId</span><span class="si">}</span><span class="sb">/comments`</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">method</span><span class="o">:</span> <span class="s1">&#39;POST&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">headers</span><span class="o">:</span> <span class="p">{</span> <span class="s1">&#39;Content-Type&#39;</span><span class="o">:</span> <span class="s1">&#39;application/json&#39;</span> <span class="p">},</span>
</span></span><span class="line"><span class="cl">        <span class="nx">body</span>: <span class="kt">JSON.stringify</span><span class="p">({</span> <span class="nx">text</span> <span class="p">}),</span>
</span></span><span class="line"><span class="cl">      <span class="p">})</span>
</span></span><span class="line"><span class="cl">      <span class="k">return</span> <span class="nx">res</span><span class="p">.</span><span class="nx">json</span><span class="p">()</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 乐观更新 - 立即显示评论
</span></span></span><span class="line"><span class="cl">    <span class="nx">onMutate</span>: <span class="kt">async</span> <span class="p">(</span><span class="nx">text</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">await</span> <span class="nx">queryClient</span><span class="p">.</span><span class="nx">cancelQueries</span><span class="p">({</span> <span class="nx">queryKey</span><span class="o">:</span> <span class="p">[</span><span class="s1">&#39;comments&#39;</span><span class="p">,</span> <span class="nx">postId</span><span class="p">]</span> <span class="p">})</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">previous</span> <span class="o">=</span> <span class="nx">queryClient</span><span class="p">.</span><span class="nx">getQueryData</span><span class="p">&lt;</span><span class="nt">Comment</span><span class="err">[]</span><span class="p">&gt;([</span><span class="s1">&#39;comments&#39;</span><span class="p">,</span> <span class="nx">postId</span><span class="p">])</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="kr">const</span> <span class="nx">optimisticComment</span>: <span class="kt">Comment</span> <span class="o">=</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">id</span><span class="o">:</span> <span class="sb">`temp-</span><span class="si">${</span><span class="nb">Date</span><span class="p">.</span><span class="nx">now</span><span class="p">()</span><span class="si">}</span><span class="sb">`</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">text</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">postId</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">        <span class="nx">createdAt</span>: <span class="kt">new</span> <span class="nb">Date</span><span class="p">().</span><span class="nx">toISOString</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">        <span class="nx">pending</span>: <span class="kt">true</span><span class="p">,</span> <span class="c1">// 在 UI 中显示&#34;发送中...&#34;的标识
</span></span></span><span class="line"><span class="cl">      <span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="nx">queryClient</span><span class="p">.</span><span class="nx">setQueryData</span><span class="p">&lt;</span><span class="nt">Comment</span><span class="err">[]</span><span class="p">&gt;(</span>
</span></span><span class="line"><span class="cl">        <span class="p">[</span><span class="s1">&#39;comments&#39;</span><span class="p">,</span> <span class="nx">postId</span><span class="p">],</span>
</span></span><span class="line"><span class="cl">        <span class="p">(</span><span class="nx">old</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">[...(</span><span class="nx">old</span> <span class="o">??</span> <span class="p">[]),</span> <span class="nx">optimisticComment</span><span class="p">]</span>
</span></span><span class="line"><span class="cl">      <span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">      <span class="k">return</span> <span class="p">{</span> <span class="nx">previous</span> <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 失败时回滚
</span></span></span><span class="line"><span class="cl">    <span class="nx">onError</span><span class="o">:</span> <span class="p">(</span><span class="nx">err</span><span class="p">,</span> <span class="nx">text</span><span class="p">,</span> <span class="nx">context</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="k">if</span> <span class="p">(</span><span class="nx">context</span><span class="o">?</span><span class="p">.</span><span class="nx">previous</span><span class="p">)</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">        <span class="nx">queryClient</span><span class="p">.</span><span class="nx">setQueryData</span><span class="p">([</span><span class="s1">&#39;comments&#39;</span><span class="p">,</span> <span class="nx">postId</span><span class="p">],</span> <span class="nx">context</span><span class="p">.</span><span class="nx">previous</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">      <span class="p">}</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="c1">// 重新拉取以获取服务器的真实数据
</span></span></span><span class="line"><span class="cl">    <span class="nx">onSettled</span><span class="o">:</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">      <span class="nx">queryClient</span><span class="p">.</span><span class="nx">invalidateQueries</span><span class="p">({</span> <span class="nx">queryKey</span><span class="o">:</span> <span class="p">[</span><span class="s1">&#39;comments&#39;</span><span class="p">,</span> <span class="nx">postId</span><span class="p">]</span> <span class="p">})</span>
</span></span><span class="line"><span class="cl">    <span class="p">},</span>
</span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>
<p>给变更设置了 <code>networkMode: 'offlineFirst'</code> 之后，<code>mutationFn</code> 会暂停到网络恢复为止。乐观更新让评论立刻出现在屏幕上，真正的 API 调用在重连时才发出去。</p>
<p>如果需要更正经的队列，比如几十个待处理变更必须按顺序重放，还可以把变更队列本身也持久化：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">MutationCache</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 将待处理的变更保存到 AsyncStorage
</span></span></span><span class="line"><span class="cl"><span class="kr">const</span> <span class="nx">mutationCache</span> <span class="o">=</span> <span class="k">new</span> <span class="nx">MutationCache</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">  <span class="nx">onError</span>: <span class="kt">async</span> <span class="p">(</span><span class="nx">error</span><span class="p">,</span> <span class="nx">variables</span><span class="p">,</span> <span class="nx">context</span><span class="p">,</span> <span class="nx">mutation</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="c1">// 记录失败的变更以便调试
</span></span></span><span class="line"><span class="cl">    <span class="kr">const</span> <span class="nx">pending</span> <span class="o">=</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">parse</span><span class="p">(</span>
</span></span><span class="line"><span class="cl">      <span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">getItem</span><span class="p">(</span><span class="s1">&#39;pending_mutations&#39;</span><span class="p">)</span> <span class="o">??</span> <span class="s1">&#39;[]&#39;</span>
</span></span><span class="line"><span class="cl">    <span class="p">)</span>
</span></span><span class="line"><span class="cl">    <span class="nx">pending</span><span class="p">.</span><span class="nx">push</span><span class="p">({</span>
</span></span><span class="line"><span class="cl">      <span class="nx">key</span>: <span class="kt">mutation.options.mutationKey</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">      <span class="nx">variables</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">      <span class="nx">timestamp</span>: <span class="kt">Date.now</span><span class="p">(),</span>
</span></span><span class="line"><span class="cl">    <span class="p">})</span>
</span></span><span class="line"><span class="cl">    <span class="k">await</span> <span class="nx">AsyncStorage</span><span class="p">.</span><span class="nx">setItem</span><span class="p">(</span><span class="s1">&#39;pending_mutations&#39;</span><span class="p">,</span> <span class="nx">JSON</span><span class="p">.</span><span class="nx">stringify</span><span class="p">(</span><span class="nx">pending</span><span class="p">))</span>
</span></span><span class="line"><span class="cl">  <span class="p">},</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span></span></span></code></pre></div></div>

<h3 class="relative group">第五步：网络回来后对齐状态
    <div id="第五步网络回来后对齐状态" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ac%ac%e4%ba%94%e6%ad%a5%e7%bd%91%e7%bb%9c%e5%9b%9e%e6%9d%a5%e5%90%8e%e5%af%b9%e9%bd%90%e7%8a%b6%e6%80%81" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>重连的活儿 React Query 基本自己包了：暂停的变更恢复执行，过期的查询重新拉取。你要做的只是把它的管理器接到 React Native 的事件上。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="kr">import</span> <span class="nx">NetInfo</span> <span class="kr">from</span> <span class="s1">&#39;@react-native-community/netinfo&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">onlineManager</span><span class="p">,</span> <span class="nx">focusManager</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;@tanstack/react-query&#39;</span>
</span></span><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">AppState</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;react-native&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 告诉 React Query 网络状态的变化
</span></span></span><span class="line"><span class="cl"><span class="nx">onlineManager</span><span class="p">.</span><span class="nx">setEventListener</span><span class="p">((</span><span class="nx">setOnline</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="nx">NetInfo</span><span class="p">.</span><span class="nx">addEventListener</span><span class="p">((</span><span class="nx">state</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">setOnline</span><span class="p">(</span><span class="o">!!</span><span class="nx">state</span><span class="p">.</span><span class="nx">isConnected</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="c1">// 应用回到前台时重新拉取
</span></span></span><span class="line"><span class="cl"><span class="nx">focusManager</span><span class="p">.</span><span class="nx">setEventListener</span><span class="p">((</span><span class="nx">setFocused</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">subscription</span> <span class="o">=</span> <span class="nx">AppState</span><span class="p">.</span><span class="nx">addEventListener</span><span class="p">(</span><span class="s1">&#39;change&#39;</span><span class="p">,</span> <span class="p">(</span><span class="nx">status</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">    <span class="nx">setFocused</span><span class="p">(</span><span class="nx">status</span> <span class="o">===</span> <span class="s1">&#39;active&#39;</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">  <span class="p">})</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="p">()</span> <span class="o">=&gt;</span> <span class="nx">subscription</span><span class="p">.</span><span class="nx">remove</span><span class="p">()</span>
</span></span><span class="line"><span class="cl"><span class="p">})</span></span></span></code></pre></div></div>
<p>用户把应用切后台一小时再回来，<code>focusManager</code> 会触发重拉，让他们看到新数据；走出隧道信号恢复时，<code>onlineManager</code> 会把暂停的操作重新跑起来。</p>

<h3 class="relative group">第六步：在 UI 上说清楚
    <div id="第六步在-ui-上说清楚" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ac%ac%e5%85%ad%e6%ad%a5%e5%9c%a8-ui-%e4%b8%8a%e8%af%b4%e6%b8%85%e6%a5%9a" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>无论如何，别把网络错误默默咽下去。要告诉用户现在离线了、哪些更改还在等待同步。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-tsx" data-lang="tsx"><span class="line"><span class="cl"><span class="kr">import</span> <span class="p">{</span> <span class="nx">useNetworkStore</span> <span class="p">}</span> <span class="kr">from</span> <span class="s1">&#39;./stores/network&#39;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">OfflineBanner() {</span>
</span></span><span class="line"><span class="cl">  <span class="kr">const</span> <span class="nx">isOnline</span> <span class="o">=</span> <span class="nx">useNetworkStore</span><span class="p">((</span><span class="nx">s</span><span class="p">)</span> <span class="o">=&gt;</span> <span class="nx">s</span><span class="p">.</span><span class="nx">isOnline</span><span class="p">)</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">if</span> <span class="p">(</span><span class="nx">isOnline</span><span class="p">)</span> <span class="k">return</span> <span class="kc">null</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;</span><span class="nt">View</span> <span class="na">style</span><span class="o">=</span><span class="p">{</span><span class="nx">styles</span><span class="p">.</span><span class="nx">banner</span><span class="p">}&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;</span><span class="nt">Text</span><span class="p">&gt;</span><span class="nx">You</span><span class="err">&#39;</span><span class="nx">re</span> <span class="nx">offline</span><span class="p">.</span> <span class="nx">Changes</span> <span class="nx">will</span> <span class="nx">sync</span> <span class="nx">when</span> <span class="nx">you</span> <span class="nx">reconnect</span><span class="p">.&lt;/</span><span class="nt">Text</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;/</span><span class="nt">View</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">  <span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl"><span class="kd">function</span> <span class="nx">CommentItem</span><span class="p">({</span> <span class="nx">comment</span> <span class="p">}</span><span class="o">:</span> <span class="p">{</span> <span class="nx">comment</span>: <span class="kt">Comment</span> <span class="p">})</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="k">return</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;</span><span class="nt">View</span> <span class="na">style</span><span class="o">=</span><span class="p">{[</span><span class="nx">styles</span><span class="p">.</span><span class="nx">comment</span><span class="p">,</span> <span class="nx">comment</span><span class="p">.</span><span class="nx">pending</span> <span class="o">&amp;&amp;</span> <span class="nx">styles</span><span class="p">.</span><span class="nx">pending</span><span class="p">]}&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">&lt;</span><span class="nt">Text</span><span class="p">&gt;{</span><span class="nx">comment</span><span class="p">.</span><span class="nx">text</span><span class="p">}&lt;/</span><span class="nt">Text</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">{</span><span class="nx">comment</span><span class="p">.</span><span class="nx">pending</span> <span class="o">&amp;&amp;</span> <span class="p">(</span>
</span></span><span class="line"><span class="cl">        <span class="p">&lt;</span><span class="nt">Text</span> <span class="na">style</span><span class="o">=</span><span class="p">{</span><span class="nx">styles</span><span class="p">.</span><span class="nx">pendingLabel</span><span class="p">}&gt;</span><span class="nx">Sending</span><span class="p">...&lt;/</span><span class="nt">Text</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">      <span class="p">)}</span>
</span></span><span class="line"><span class="cl">    <span class="p">&lt;/</span><span class="nt">View</span><span class="p">&gt;</span>
</span></span><span class="line"><span class="cl">  <span class="p">)</span>
</span></span><span class="line"><span class="cl"><span class="p">}</span></span></span></code></pre></div></div>

<h3 class="relative group">整体架构
    <div id="整体架构" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e6%95%b4%e4%bd%93%e6%9e%b6%e6%9e%84" aria-label="锚点">#</a>
    </span>
    
</h3>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-text" data-lang="text"><span class="line"><span class="cl">┌─────────────────────────────────────────────────┐
</span></span><span class="line"><span class="cl">│                   Components                     │
</span></span><span class="line"><span class="cl">│  useQuery() for reads    useMutation() for writes│
</span></span><span class="line"><span class="cl">└──────────┬──────────────────────┬────────────────┘
</span></span><span class="line"><span class="cl">           │                      │
</span></span><span class="line"><span class="cl">     ┌─────▼──────┐        ┌─────▼──────┐
</span></span><span class="line"><span class="cl">     │ React Query │        │ React Query │
</span></span><span class="line"><span class="cl">     │   Cache     │        │  Mutation   │
</span></span><span class="line"><span class="cl">     │ (in-memory) │        │   Queue     │
</span></span><span class="line"><span class="cl">     └─────┬──────┘        └─────┬──────┘
</span></span><span class="line"><span class="cl">           │                      │
</span></span><span class="line"><span class="cl">     ┌─────▼──────────────────────▼──────┐
</span></span><span class="line"><span class="cl">     │     AsyncStorage Persister         │
</span></span><span class="line"><span class="cl">     │  (survives app restart)            │
</span></span><span class="line"><span class="cl">     └─────┬──────────────────────┬──────┘
</span></span><span class="line"><span class="cl">           │                      │
</span></span><span class="line"><span class="cl">     ┌─────▼──────┐        ┌─────▼──────┐
</span></span><span class="line"><span class="cl">     │   Zustand   │        │   Network  │
</span></span><span class="line"><span class="cl">     │ (isOnline,  │◄───────│   NetInfo  │
</span></span><span class="line"><span class="cl">     │  UI state)  │        │            │
</span></span><span class="line"><span class="cl">     └────────────┘        └────────────┘</span></span></code></pre></div></div>
<table>
	<thead>
			<tr>
					<th>层</th>
					<th>工具</th>
					<th>职责</th>
			</tr>
	</thead>
	<tbody>
			<tr>
					<td>网络检测</td>
					<td>Zustand + NetInfo</td>
					<td>跟踪在线/离线状态，驱动 UI 横幅</td>
			</tr>
			<tr>
					<td>数据拉取</td>
					<td>React Query</td>
					<td>在线时拉取，离线时返回缓存</td>
			</tr>
			<tr>
					<td>缓存持久化</td>
					<td>React Query + AsyncStorage</td>
					<td>应用重启时恢复缓存</td>
			</tr>
			<tr>
					<td>离线写入</td>
					<td>React Query mutations</td>
					<td>变更排队，重连后重放</td>
			</tr>
			<tr>
					<td>乐观 UI</td>
					<td>React Query <code>onMutate</code></td>
					<td>立即显示更改，失败时回滚</td>
			</tr>
			<tr>
					<td>前台同步</td>
					<td>React Query <code>focusManager</code></td>
					<td>应用回到前台时重新拉取过期数据</td>
			</tr>
	</tbody>
</table>

<h3 class="relative group">什么时候需要真正的同步引擎
    <div id="什么时候需要真正的同步引擎" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e4%bb%80%e4%b9%88%e6%97%b6%e5%80%99%e9%9c%80%e8%a6%81%e7%9c%9f%e6%ad%a3%e7%9a%84%e5%90%8c%e6%ad%a5%e5%bc%95%e6%93%8e" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>上面这套的前提是：服务器是数据的真实来源，离线只是暂时状态。如果你要的是带冲突解决的真·离线优先，比如两台设备离线编辑同一篇笔记，这套就不够了，得上专门的同步引擎。WatermelonDB 专为 React Native 打造，底层是 SQLite，自带解决冲突的同步协议。Realm 配上 Atlas Device Sync，就是一个通过 MongoDB Atlas 自动解决冲突的完整离线优先数据库。PowerSync 是基于 SQLite 的同步层，能直接对接你现有的 Postgres 后端。要完全的控制权，也可以 Expo SQLite 加自己写同步逻辑。</p>
<p>Zustand + React Query + AsyncStorage 能覆盖大约 80% 的移动应用。剩下的 20%，也就是协同编辑、多设备同步、重度离线的工作流，需要专门的同步数据库。</p>

<h2 class="relative group">拿不准放哪时
    <div id="拿不准放哪时" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e6%8b%bf%e4%b8%8d%e5%87%86%e6%94%be%e5%93%aa%e6%97%b6" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>我拿不准的时候，会按这个顺序问自己：</p>
<table>
	<thead>
			<tr>
					<th>问题</th>
					<th>是 → 用</th>
			</tr>
	</thead>
	<tbody>
			<tr>
					<td>数据来自服务器/API 吗？</td>
					<td>React Query</td>
			</tr>
			<tr>
					<td>是多个组件共享的纯客户端 UI 状态吗？</td>
					<td>Zustand</td>
			</tr>
			<tr>
					<td>需要扛过应用重启吗？</td>
					<td>AsyncStorage（可选配合 Zustand persist）</td>
			</tr>
			<tr>
					<td>是敏感数据吗（令牌、密码）？</td>
					<td>expo-secure-store / react-native-keychain</td>
			</tr>
			<tr>
					<td>是需要查询的大型结构化数据吗？</td>
					<td>SQLite / WatermelonDB / Realm</td>
			</tr>
			<tr>
					<td>只是单个组件用的简单表单输入吗？</td>
					<td>useState</td>
			</tr>
	</tbody>
</table>

<h3 class="relative group">常见场景
    <div id="常见场景" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e5%b8%b8%e8%a7%81%e5%9c%ba%e6%99%af" aria-label="锚点">#</a>
    </span>
    
</h3>
<table>
	<thead>
			<tr>
					<th>状态</th>
					<th>工具</th>
					<th>原因</th>
			</tr>
	</thead>
	<tbody>
			<tr>
					<td>API 响应数据</td>
					<td>React Query</td>
					<td>缓存、去重、重新拉取、加载状态</td>
			</tr>
			<tr>
					<td>选中的标签页 / 当前筛选条件</td>
					<td>Zustand</td>
					<td>纯客户端，多个组件都要用</td>
			</tr>
			<tr>
					<td>认证令牌</td>
					<td>AsyncStorage + Zustand</td>
					<td>重启后仍在，内存中读取快</td>
			</tr>
			<tr>
					<td>主题偏好</td>
					<td>Zustand + persist 中间件</td>
					<td>需要扛过重启的客户端状态</td>
			</tr>
			<tr>
					<td>购物车</td>
					<td>Zustand + persist 中间件</td>
					<td>客户端逻辑复杂，需要扛过重启</td>
			</tr>
			<tr>
					<td>表单输入</td>
					<td>useState</td>
					<td>只在单个组件里用，无需共享</td>
			</tr>
			<tr>
					<td>来自 API 的用户资料</td>
					<td>React Query</td>
					<td>服务器状态，可能过期</td>
			</tr>
			<tr>
					<td>引导完成标记</td>
					<td>AsyncStorage</td>
					<td>只是一个需要持久化的布尔值</td>
			</tr>
			<tr>
					<td>离线缓存的动态流</td>
					<td>React Query + AsyncStorage</td>
					<td>从服务器拉取，失败时退回缓存</td>
			</tr>
	</tbody>
</table>

<h2 class="relative group">各平台安装
    <div id="各平台安装" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e5%90%84%e5%b9%b3%e5%8f%b0%e5%ae%89%e8%a3%85" aria-label="锚点">#</a>
    </span>
    
</h2>

<h3 class="relative group">React Native (Android + iOS)
    <div id="react-native-android--ios" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#react-native-android--ios" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>三个一起装：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"><span class="line"><span class="cl">npm install zustand @tanstack/react-query @react-native-async-storage/async-storage</span></span></code></pre></div></div>
<p>敏感数据再加上安全存储：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"><span class="line"><span class="cl">npx expo install expo-secure-store
</span></span><span class="line"><span class="cl"><span class="c1"># 或者</span>
</span></span><span class="line"><span class="cl">npm install react-native-keychain</span></span></code></pre></div></div>

<h3 class="relative group">Expo
    <div id="expo" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#expo" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>AsyncStorage 在 Expo 里开箱即用，不需要原生链接。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"><span class="line"><span class="cl">npx expo install @react-native-async-storage/async-storage</span></span></code></pre></div></div>

<h3 class="relative group">纯 Web React
    <div id="纯-web-react" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e7%ba%af-web-react" aria-label="锚点">#</a>
    </span>
    
</h3>
<p>跳过 AsyncStorage，直接用 <code>localStorage</code> 或 <code>IndexedDB</code>。</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"><span class="line"><span class="cl">npm install zustand @tanstack/react-query
</span></span><span class="line"><span class="cl"><span class="c1"># 可选，用于 IndexedDB</span>
</span></span><span class="line"><span class="cl">npm install idb-keyval</span></span></code></pre></div></div>
<p>Zustand 的 persist 中间件在 Web 上默认就用 <code>localStorage</code>：</p>
<div class="highlight-wrapper"><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-typescript" data-lang="typescript"><span class="line"><span class="cl"><span class="nx">persist</span><span class="p">(</span><span class="nx">storeConfig</span><span class="p">,</span> <span class="p">{</span>
</span></span><span class="line"><span class="cl">  <span class="nx">name</span><span class="o">:</span> <span class="s1">&#39;my-store&#39;</span><span class="p">,</span>
</span></span><span class="line"><span class="cl">  <span class="c1">// localStorage 在 Web 端是默认的 - 不需要额外配置
</span></span></span><span class="line"><span class="cl"><span class="p">})</span></span></span></code></pre></div></div>

<h2 class="relative group">我反复见到的错误
    <div id="我反复见到的错误" class="anchor"></div>
    
    <span
        class="absolute top-0 w-6 transition-opacity opacity-0 -start-6 not-prose group-hover:opacity-100 select-none">
        <a class="text-primary-300 dark:text-neutral-700 !no-underline" href="#%e6%88%91%e5%8f%8d%e5%a4%8d%e8%a7%81%e5%88%b0%e7%9a%84%e9%94%99%e8%af%af" aria-label="锚点">#</a>
    </span>
    
</h2>
<p>把 API 数据塞进 Zustand。如果你的 action 里出现了 <code>setUsers(apiResponse.users)</code>，先停一下。那是 React Query 的活，再往前走一步，就是把缓存失效重新发明一遍，而且发明得不会太好。</p>
<p>用 React Query 管客户端状态。<code>queryFn</code> 里没有网络请求？工具用错了。</p>
<p>把 AsyncStorage 当数据库。往键值存储里序列化一万条记录的数组，结局不会体面。用数据库。</p>
<p>令牌不加密。AsyncStorage 不是安全存储。认证令牌、API 密钥、用户凭证，请放 <code>expo-secure-store</code> 或平台的 keychain。</p>
<p>手搓持久化。如果你在挂载时手动读 AsyncStorage、每次状态一变就手动写回去，Zustand 的 persist 中间件早就把这些连同水合、序列化一起做好了，代码更少，坑也更少。</p>
<hr>
<p>服务器数据走 React Query。客户端状态放 Zustand。要扛过重启的进 AsyncStorage，敏感的进安全存储。</p>
<p>我经手过的最糟的架构，无一例外都是所有东西流经一个巨型 store。好的架构里，服务器状态、客户端状态、需要持久化的东西之间有清清楚楚的线。这些线画得越早，后面的一切就越省事。</p>
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