React 与 React Native 的状态管理 · 1.0
共享状态。一个 Hook。搞定。
一行声明一个 store,在任何组件中使用——无需 Provider、action 或 reducer。组件只在选取的值变化时渲染,何时保存由你决定。
npm install @kkwaenggwari/restate实时演示 — 一个真正的 restate store
useCart.set(cart => ({ ...cart, items: cart.items + 1, total: cart.total + 12 }))items 和 total 变化——三张卡片渲染,留言保持不动。
01 — 简单
同样的功能,更少的概念。
同一个任务的四种实现并排展示。数字来自这里显示的代码,在构建本站时测量。
共享计数器
两个组件读取并更新同一个数字。
Redux Toolkit 把更新组织成 slice 和 action,并 dispatch 到通过 React context 提供的 store。 出色的 DevTools,以及适合大型团队的严格、可预测的更新流程。
Zustand 用 create() 创建 store Hook,用 setState 修改它。 极小且灵活,有用于持久化和 DevTools 的中间件。
Jotai 组合 atom 和派生 atom,可选择放在 Provider 中。 大量小状态之间的细粒度依赖。
import { configureStore, createSlice } from '@reduxjs/toolkit';
import { Provider, useDispatch, useSelector } from 'react-redux';
const slice = createSlice({
name: 'count',
initialState: 0,
reducers: { increment: (count) => count + 1 },
});
const store = configureStore({
reducer: { count: slice.reducer },
});
function Counter() {
const count = useSelector((state) => state.count);
const dispatch = useDispatch();
return <button onClick={() => dispatch(slice.actions.increment())}>{count}</button>;
}
export default function App() {
return (
<Provider store={store}>
<Counter />
<Counter />
</Provider>
);
}import { create } from 'zustand';
const useCount = create(() => ({ count: 0 }));
const increment = () =>
useCount.setState((s) => ({
count: s.count + 1,
}));
function Counter() {
const count = useCount((s) => s.count);
return <button onClick={increment}>{count}</button>;
}
export default function App() {
return (
<>
<Counter />
<Counter />
</>
);
}import { atom, useAtom } from 'jotai';
const countAtom = atom(0);
function Counter() {
const [count, setCount] = useAtom(countAtom);
return <button onClick={() => setCount((n) => n + 1)}>{count}</button>;
}
export default function App() {
return (
<>
<Counter />
<Counter />
</>
);
}restate 一个声明既是 store,也是 Hook。
import { restate } from '@kkwaenggwari/restate';
const useCount = restate(0);
function Counter() {
const count = useCount();
return <button onClick={() => useCount.set((n) => n + 1)}>{count}</button>;
}
export default function App() {
return (
<>
<Counter />
<Counter />
</>
);
}在这个任务上,Zustand 和 Jotai 同样小巧、无需 Provider。一旦涉及保存和按文档区分的状态,差距才会拉开。
选取一个字段
只有正文变化时,标题组件不能渲染。
Redux Toolkit 把更新组织成 slice 和 action,并 dispatch 到通过 React context 提供的 store。 出色的 DevTools,以及适合大型团队的严格、可预测的更新流程。
Zustand 用 create() 创建 store Hook,用 setState 修改它。 极小且灵活,有用于持久化和 DevTools 的中间件。
Jotai 组合 atom 和派生 atom,可选择放在 Provider 中。 大量小状态之间的细粒度依赖。
import { configureStore, createSlice } from '@reduxjs/toolkit';
import { Provider, useSelector } from 'react-redux';
const article = createSlice({
name: 'article',
initialState: { title: 'Hello', body: '' },
reducers: {
editBody: (i) => {
i.body += '!';
},
editTitle: (i) => {
i.title += '!';
},
},
});
const store = configureStore({ reducer: article.reducer });
function Title() {
const title = useSelector((i) => i.title);
return <h3>{title}</h3>;
}
export default function App() {
return (
<Provider store={store}>
<Title />
<button onClick={() => store.dispatch(article.actions.editBody())}>body + !</button>
<button onClick={() => store.dispatch(article.actions.editTitle())}>title + !</button>
</Provider>
);
}import { create } from 'zustand';
const useArticle = create(() => ({ title: 'Hello', body: '' }));
function Title() {
const title = useArticle((i) => i.title);
return <h3>{title}</h3>;
}
export default function App() {
return (
<>
<Title />
<button
onClick={() =>
useArticle.setState((i) => ({
body: i.body + '!',
}))
}
>
body + !
</button>
<button
onClick={() =>
useArticle.setState((i) => ({
title: i.title + '!',
}))
}
>
title + !
</button>
</>
);
}import { atom, useAtomValue, useSetAtom } from 'jotai';
const articleAtom = atom({ title: 'Hello', body: '' });
const titleAtom = atom((get) => get(articleAtom).title);
function Title() {
const title = useAtomValue(titleAtom);
return <h3>{title}</h3>;
}
export default function App() {
const setArticle = useSetAtom(articleAtom);
return (
<>
<Title />
<button
onClick={() =>
setArticle((i) => ({
...i,
body: i.body + '!',
}))
}
>
body + !
</button>
<button
onClick={() =>
setArticle((i) => ({
...i,
title: i.title + '!',
}))
}
>
title + !
</button>
</>
);
}restate 把 selector 传给你已经在用的同一个 Hook。
import { restate } from '@kkwaenggwari/restate';
const useArticle = restate({ title: 'Hello', body: '' });
function Title() {
const title = useArticle((i) => i.title);
return <h3>{title}</h3>;
}
export default function App() {
return (
<>
<Title />
<button
onClick={() =>
useArticle.set((i) => ({
...i,
body: i.body + '!',
}))
}
>
body + !
</button>
<button
onClick={() =>
useArticle.set((i) => ({
...i,
title: i.title + '!',
}))
}
>
title + !
</button>
</>
);
}这里的每个工具都能做选取。restate 用的是同一个 Hook 调用,而不是单独的 selector Hook 或派生 atom。
保存草稿
启动时恢复已保存的草稿,点击时保存,并显示保存中、未保存和失败状态。
Redux Toolkit 把更新组织成 slice 和 action,并 dispatch 到通过 React context 提供的 store。 出色的 DevTools,以及适合大型团队的严格、可预测的更新流程。
Zustand 用 create() 创建 store Hook,用 setState 修改它。 极小且灵活,有用于持久化和 DevTools 的中间件。
Jotai 组合 atom 和派生 atom,可选择放在 Provider 中。 大量小状态之间的细粒度依赖。
import { useEffect, useState } from 'react';
import { configureStore, createSlice } from '@reduxjs/toolkit';
import { Provider, useSelector } from 'react-redux';
function openDraftDB() {
return new Promise((resolve, reject) => {
const request = indexedDB.open('draft-example', 1);
let blocked = false;
request.onupgradeneeded = () => {
request.result.createObjectStore('drafts');
};
request.onblocked = () => {
blocked = true;
reject(new Error('Close other tabs to upgrade storage'));
};
request.onerror = () => reject(request.error);
request.onsuccess = () => {
const db = request.result;
if (blocked) {
db.close();
return;
}
db.onversionchange = () => db.close();
resolve(db);
};
});
}
async function storedDraft(mode, text) {
const db = await openDraftDB();
try {
return await new Promise((resolve, reject) => {
const tx = db.transaction('drafts', mode);
const store = tx.objectStore('drafts');
const request = mode === 'readonly' ? store.get('draft') : store.put(text, 'draft');
tx.oncomplete = () => resolve(request.result);
tx.onabort = () => reject(tx.error || new Error('Storage aborted'));
});
} finally {
db.close();
}
}
const draft = createSlice({
name: 'draft',
initialState: '',
reducers: { edit: (_, action) => action.payload },
});
const store = configureStore({ reducer: { draft: draft.reducer } });
const hydrated = storedDraft('readonly').then((saved) => {
if (saved === undefined) return;
if (typeof saved !== 'string') throw new Error('Invalid draft');
const value = saved;
store.dispatch(draft.actions.edit(value));
});
// Observe errors immediately, even before the component mounts.
hydrated.catch(() => {});
function DraftEditor() {
const text = useSelector((state) => state.draft);
const [ready, setReady] = useState(false);
const [saving, setSaving] = useState(false);
const [message, setMessage] = useState('Loading');
useEffect(() => {
let active = true;
hydrated.then(
() => {
if (active) {
setReady(true);
setMessage('Ready');
}
},
() => {
if (active) setMessage('Storage error');
},
);
return () => {
active = false;
};
}, []);
async function save() {
setSaving(true);
try {
await storedDraft('readwrite', store.getState().draft);
setMessage('Saved');
} catch {
setMessage('Save failed');
} finally {
setSaving(false);
}
}
return (
<>
<label>
Draft
<textarea
value={text}
disabled={!ready || saving}
onChange={(event) => {
const value = event.target.value;
store.dispatch(draft.actions.edit(value));
setMessage('Edited');
}}
/>
</label>
<output>{text}</output>
<button disabled={!ready || saving} onClick={save}>
Save
</button>
<p>{message}</p>
</>
);
}
export default function App() {
return (
<Provider store={store}>
<DraftEditor />
</Provider>
);
}import { useEffect, useState } from 'react';
import { create } from 'zustand';
function openDraftDB() {
return new Promise((resolve, reject) => {
const request = indexedDB.open('draft-example', 1);
let blocked = false;
request.onupgradeneeded = () => {
request.result.createObjectStore('drafts');
};
request.onblocked = () => {
blocked = true;
reject(new Error('Close other tabs to upgrade storage'));
};
request.onerror = () => reject(request.error);
request.onsuccess = () => {
const db = request.result;
if (blocked) {
db.close();
return;
}
db.onversionchange = () => db.close();
resolve(db);
};
});
}
async function storedDraft(mode, text) {
const db = await openDraftDB();
try {
return await new Promise((resolve, reject) => {
const tx = db.transaction('drafts', mode);
const store = tx.objectStore('drafts');
const request = mode === 'readonly' ? store.get('draft') : store.put(text, 'draft');
tx.oncomplete = () => resolve(request.result);
tx.onabort = () => reject(tx.error || new Error('Storage aborted'));
});
} finally {
db.close();
}
}
const useDraft = create(() => ({ text: '' }));
const hydrated = storedDraft('readonly').then((saved) => {
if (saved === undefined) return;
if (typeof saved !== 'string') throw new Error('Invalid draft');
const value = saved;
useDraft.setState({ text: value });
});
// Observe errors immediately, even before the component mounts.
hydrated.catch(() => {});
function DraftEditor() {
const text = useDraft((state) => state.text);
const [ready, setReady] = useState(false);
const [saving, setSaving] = useState(false);
const [message, setMessage] = useState('Loading');
useEffect(() => {
let active = true;
hydrated.then(
() => {
if (active) {
setReady(true);
setMessage('Ready');
}
},
() => {
if (active) setMessage('Storage error');
},
);
return () => {
active = false;
};
}, []);
async function save() {
setSaving(true);
try {
await storedDraft('readwrite', useDraft.getState().text);
setMessage('Saved');
} catch {
setMessage('Save failed');
} finally {
setSaving(false);
}
}
return (
<>
<label>
Draft
<textarea
value={text}
disabled={!ready || saving}
onChange={(event) => {
const value = event.target.value;
useDraft.setState({ text: value });
setMessage('Edited');
}}
/>
</label>
<output>{text}</output>
<button disabled={!ready || saving} onClick={save}>
Save
</button>
<p>{message}</p>
</>
);
}
export default function App() {
return <DraftEditor />;
}import { useEffect, useState } from 'react';
import { atom, createStore, useAtomValue } from 'jotai';
function openDraftDB() {
return new Promise((resolve, reject) => {
const request = indexedDB.open('draft-example', 1);
let blocked = false;
request.onupgradeneeded = () => {
request.result.createObjectStore('drafts');
};
request.onblocked = () => {
blocked = true;
reject(new Error('Close other tabs to upgrade storage'));
};
request.onerror = () => reject(request.error);
request.onsuccess = () => {
const db = request.result;
if (blocked) {
db.close();
return;
}
db.onversionchange = () => db.close();
resolve(db);
};
});
}
async function storedDraft(mode, text) {
const db = await openDraftDB();
try {
return await new Promise((resolve, reject) => {
const tx = db.transaction('drafts', mode);
const store = tx.objectStore('drafts');
const request = mode === 'readonly' ? store.get('draft') : store.put(text, 'draft');
tx.oncomplete = () => resolve(request.result);
tx.onabort = () => reject(tx.error || new Error('Storage aborted'));
});
} finally {
db.close();
}
}
const draftAtom = atom('');
const store = createStore();
const hydrated = storedDraft('readonly').then((saved) => {
if (saved === undefined) return;
if (typeof saved !== 'string') throw new Error('Invalid draft');
const value = saved;
store.set(draftAtom, value);
});
// Observe errors immediately, even before the component mounts.
hydrated.catch(() => {});
function DraftEditor() {
const text = useAtomValue(draftAtom, { store });
const [ready, setReady] = useState(false);
const [saving, setSaving] = useState(false);
const [message, setMessage] = useState('Loading');
useEffect(() => {
let active = true;
hydrated.then(
() => {
if (active) {
setReady(true);
setMessage('Ready');
}
},
() => {
if (active) setMessage('Storage error');
},
);
return () => {
active = false;
};
}, []);
async function save() {
setSaving(true);
try {
await storedDraft('readwrite', store.get(draftAtom));
setMessage('Saved');
} catch {
setMessage('Save failed');
} finally {
setSaving(false);
}
}
return (
<>
<label>
Draft
<textarea
value={text}
disabled={!ready || saving}
onChange={(event) => {
const value = event.target.value;
store.set(draftAtom, value);
setMessage('Edited');
}}
/>
</label>
<output>{text}</output>
<button disabled={!ready || saving} onClick={save}>
Save
</button>
<p>{message}</p>
</>
);
}
export default function App() {
return <DraftEditor />;
}restate persistedRestate 会自动恢复,useStatus 会报告保存进度、未保存的修改和错误。
import { persistedRestate } from '@kkwaenggwari/restate';
const useDraft = persistedRestate('', {
key: 'draft',
validate: (value) => typeof value === 'string',
});
export default function App() {
const text = useDraft();
const { dirty, operation, error } = useDraft.useStatus();
const saving = operation === 'save';
const message = error ? 'Save failed' : saving ? 'Saving…' : dirty ? 'Edited' : 'Saved';
return (
<>
<label>
Draft
<textarea value={text} onChange={(event) => useDraft.set(event.target.value)} />
</label>
<output>{text}</output>
<button disabled={saving} onClick={() => useDraft.save().catch(() => {})}>
Save
</button>
<p>{message}</p>
</>
);
}其他版本都手写了相同的 IndexedDB 代码。它们的持久化中间件或存储工具可以借助适配器缩短代码,但这里没有计入那部分代码。
按文档区分的状态
两个文档各自保持独立的状态,关闭一个就会释放它。
Redux Toolkit 把更新组织成 slice 和 action,并 dispatch 到通过 React context 提供的 store。 出色的 DevTools,以及适合大型团队的严格、可预测的更新流程。
Zustand 用 create() 创建 store Hook,用 setState 修改它。 极小且灵活,有用于持久化和 DevTools 的中间件。
Jotai 组合 atom 和派生 atom,可选择放在 Provider 中。 大量小状态之间的细粒度依赖。
import { useState } from 'react';
import { configureStore, createSlice } from '@reduxjs/toolkit';
import { Provider, useSelector } from 'react-redux';
const draft = createSlice({
name: 'draft',
initialState: '',
reducers: { edit: (_, action) => action.payload },
});
const selectionSlice = createSlice({
name: 'selection',
initialState: 0,
reducers: { next: (index) => index + 1 },
});
function createDocument() {
return {
store: configureStore({
reducer: {
draft: draft.reducer,
selection: selectionSlice.reducer,
},
}),
};
}
function Document({ doc, name }) {
const text = useSelector((state) => state.draft);
const selection = useSelector((state) => state.selection);
return (
<section>
<label>
{name}
<input
value={text}
onChange={(event) => doc.store.dispatch(draft.actions.edit(event.target.value))}
/>
</label>
<output>{text}</output>
<button onClick={() => doc.store.dispatch(selectionSlice.actions.next())}>
Selection: {selection}
</button>
</section>
);
}
function DocumentSlot({ name }) {
const [doc] = useState(createDocument);
return (
<Provider store={doc.store}>
<Document doc={doc} name={name} />
</Provider>
);
}
export default function App() {
const [leftOpen, setLeftOpen] = useState(true);
return (
<>
<button onClick={() => setLeftOpen((open) => !open)}>
{leftOpen ? 'Close left' : 'Open left'}
</button>
{leftOpen && <DocumentSlot name="Left" />}
<DocumentSlot name="Right" />
</>
);
}import { useState } from 'react';
import { useStore } from 'zustand';
import { createStore } from 'zustand/vanilla';
function createDocument() {
return {
draft: createStore(() => ({ text: '' })),
selection: createStore(() => ({ index: 0 })),
};
}
function Document({ doc, name }) {
const text = useStore(doc.draft, (state) => state.text);
const selection = useStore(doc.selection, (state) => state.index);
return (
<section>
<label>
{name}
<input
value={text}
onChange={(event) => doc.draft.setState({ text: event.target.value })}
/>
</label>
<output>{text}</output>
<button onClick={() => doc.selection.setState((s) => ({ index: s.index + 1 }))}>
Selection: {selection}
</button>
</section>
);
}
function DocumentSlot({ name }) {
const [doc] = useState(createDocument);
return <Document doc={doc} name={name} />;
}
export default function App() {
const [leftOpen, setLeftOpen] = useState(true);
return (
<>
<button onClick={() => setLeftOpen((open) => !open)}>
{leftOpen ? 'Close left' : 'Open left'}
</button>
{leftOpen && <DocumentSlot name="Left" />}
<DocumentSlot name="Right" />
</>
);
}import { useState } from 'react';
import { atom, createStore, useAtomValue } from 'jotai';
const draftAtom = atom('');
const selectionAtom = atom(0);
function createDocument() {
return { store: createStore() };
}
function Document({ doc, name }) {
const text = useAtomValue(draftAtom, { store: doc.store });
const selection = useAtomValue(selectionAtom, { store: doc.store });
return (
<section>
<label>
{name}
<input value={text} onChange={(event) => doc.store.set(draftAtom, event.target.value)} />
</label>
<output>{text}</output>
<button onClick={() => doc.store.set(selectionAtom, (n) => n + 1)}>
Selection: {selection}
</button>
</section>
);
}
function DocumentSlot({ name }) {
const [doc] = useState(createDocument);
return <Document doc={doc} name={name} />;
}
export default function App() {
const [leftOpen, setLeftOpen] = useState(true);
return (
<>
<button onClick={() => setLeftOpen((open) => !open)}>
{leftOpen ? 'Close left' : 'Open left'}
</button>
{leftOpen && <DocumentSlot name="Left" />}
<DocumentSlot name="Right" />
</>
);
}restate useRestateScope 创建 store,并在卸载后销毁它们。
import { useState } from 'react';
import { restate, useRestateScope } from '@kkwaenggwari/restate';
function Document({ name }) {
const doc = useRestateScope((scope) => ({
useDraft: restate('', { scope }),
useSelection: restate(0, { scope }),
}));
const text = doc.useDraft();
const selection = doc.useSelection();
return (
<section>
<label>
{name}
<input value={text} onChange={(event) => doc.useDraft.set(event.target.value)} />
</label>
<output>{text}</output>
<button onClick={() => doc.useSelection.set((n) => n + 1)}>Selection: {selection}</button>
</section>
);
}
export default function App() {
const [leftOpen, setLeftOpen] = useState(true);
return (
<>
<button onClick={() => setLeftOpen((open) => !open)}>
{leftOpen ? 'Close left' : 'Open left'}
</button>
{leftOpen && <Document name="Left" />}
<Document name="Right" />
</>
);
}Jotai 的 Provider 或 store、Zustand 的 vanilla store 也能隔离状态,但需要你自己创建和连接。
这些数字怎么算
统计的是所示代码的非空行数,以及从各状态库导入的名称数量(不计 React 的导入)。每个版本都以相同的存储、加载和错误状态渲染相同的 UI。restate 示例假定应用入口已执行 await restateManager.ready。源码已对照各项目的官方文档核实:
- Redux Toolkit — Redux Toolkit · Quick Start, React Redux · useSelector, Redux Toolkit · configureStore. 当一条可审计的 action 日志和庞大的中间件生态最重要时选择它
- Zustand — Zustand · Introduction, Zustand · persist. 当你想要最小的核心、喜欢组合中间件时选择它
- Jotai — Jotai · atom, Jotai · Storage, Jotai · Provider. 当你的状态天然就是一张由小的派生值组成的图时选择它
02 — 快速
只渲染变化的部分,只写入一次。
两个面板都在浏览器中运行真正的 restate 包。点一点、打打字,看看计数器。
渲染地图
用两种方式读取同样的四个字段。改一个字段,数一数渲染次数。
- 名称
- 主题
- 计数
- 草稿
- 名称
- 主题
- 计数
- 草稿
合并写入
autoSave 等到输入停顿后只写入一次。连续调用 save() 会共享队列中的同一次写入。
persistedRestate('', { key: 'note', autoSave: { delayMs: 400 } });次数来自本页真实的 React 渲染,以及一个会计数的存储适配器。其他库也能选取值;在 restate 中,选取就是读取值的方式。
- 01
保存按顺序执行
每个 store 依次执行自己的存储操作,所以缓慢的保存绝不会让旧值覆盖新值。
save() · restore() - 02
排队中的保存会写入最新值
在另一次保存排队时调用 save(),会合并进那次保存,而不是叠加更多写入。
save(): Promise<T> - 03
未读取的记录不会被意外覆盖
如果某条记录加载失败,autoSave 和批量保存不会动它,并报告 LOAD_FAILED。只有显式调用 save() 才能替换它。
LOAD_FAILED - 04
即使卸载,保存也会完成
卸载前请求的保存会完成。之后对已销毁 store 的写入会被忽略,就像卸载后的 React state 一样。
useRestateScope - 05
没有存储?应用照样启动
在服务端渲染或存储被禁用时,store 会继续在内存中工作,并报告存储不可用。
status().available - 06
错误会说明是什么、在哪里
每个 restate 错误都带有类型化的错误码和对应记录的 key,方便你显示合适的提示。
error.code · error.key
随应用一起成长
只改声明,组件不动。
保存、自动保存和校验都是同一个 store 的选项。右侧的组件始终不变。
内存
内存中的共享值。
import { restate } from '@kkwaenggwari/restate'; export const useDraft = restate('');持久化
自动恢复;调用 save() 时写入。
import { persistedRestate } from '@kkwaenggwari/restate'; export const useDraft = persistedRestate('', { key: 'draft' });自动保存
输入停顿 500 ms 后写入一次。
import { persistedRestate } from '@kkwaenggwari/restate'; export const useDraft = persistedRestate('', { key: 'draft', autoSave: { delayMs: 500 }, });带校验
旧记录在使用前会先迁移并检查。
import { persistedRestate } from '@kkwaenggwari/restate'; export const useDraft = persistedRestate('', { key: 'draft', autoSave: { delayMs: 500 }, version: 2, migrate: (value) => String(value ?? ''), validate: (value) => typeof value === 'string', });
组件 — 每一步都不变
function Editor() {
const text = useDraft();
return <textarea value={text} onChange={(event) => useDraft.set(event.target.value)} />;
}React 能跑的地方它都能跑
一个包,覆盖所有 React 环境。
react >=16.8.0React
支持 React 16.8 及以上版本,浏览器和服务端渲染都可以用。
react-native-mmkv >=2.0.0React Native
import 完全相同。安装 react-native-mmkv 后,保存会使用 MMKV。
SSR服务端渲染
组件拥有的 store 从 props 获取服务端快照,并在水合后开始加载。
index.d.tsTypeScript
自带类型声明。selector、状态字段和错误码都有类型。
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