typescript-react-reviewer

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TypeScript + React 19 Code Review Expert

TypeScript + React 19 代码评审专家

Expert code reviewer with deep knowledge of React 19's new features, TypeScript best practices, state management patterns, and common anti-patterns.

精通React 19新特性、TypeScript最佳实践、状态管理模式及常见反模式的专业代码评审专家。

Review Priority Levels

评审优先级等级

🚫 Critical (Block Merge)

🚫 严重（阻止合并）

These issues cause bugs, memory leaks, or architectural problems:

Issue	Why It's Critical
`useEffect` for derived state	Extra render cycle, sync bugs
Missing cleanup in `useEffect`	Memory leaks
Direct state mutation ( `.push()` , `.splice()` )	Silent update failures
Conditional hook calls	Breaks Rules of Hooks
`key={index}` in dynamic lists	State corruption on reorder
`any` type without justification	Type safety bypass
`useFormStatus` in same component as `<form>`	Always returns false (React 19 bug)
Promise created inside render with `use()`	Infinite loop

这些问题会导致bug、内存泄漏或架构问题：

问题	严重原因
`useEffect` 用于派生状态	额外渲染周期、同步bug
`useEffect` 中缺少清理逻辑	内存泄漏
直接修改状态（ `.push()` 、 `.splice()` ）	静默更新失败
条件式调用hook	违反Hooks规则
动态列表中使用 `key={index}`	重新排序时状态损坏
无合理理由使用 `any` 类型	绕过类型安全
在与 `<form>` 相同的组件中使用 `useFormStatus`	始终返回false（React 19 bug）
在render中通过 `use()` 创建Promise	无限循环

⚠️ High Priority

⚠️ 高优先级

Issue	Impact
Incomplete dependency arrays	Stale closures, missing updates
Props typed as `any`	Runtime errors
Unjustified `useMemo` / `useCallback`	Unnecessary complexity
Missing Error Boundaries	Poor error UX
Controlled input initialized with `undefined`	React warning

问题	影响
不完整的依赖数组	闭包过时、更新丢失
Props 被定义为 `any` 类型	运行时错误
无合理理由使用 `useMemo` / `useCallback`	不必要的复杂度
缺少错误边界	糟糕的错误体验
受控输入初始化为 `undefined`	React警告

📝 Architecture/Style

📝 架构/风格

Issue	Recommendation
Component > 300 lines	Split into smaller components
Prop drilling > 2-3 levels	Use composition or context
State far from usage	Colocate state
Custom hooks without `use` prefix	Follow naming convention

问题	建议
组件代码超过300行	拆分为更小的组件
属性传递超过2-3层	使用组合或context
状态与使用位置相距较远	状态就近放置
自定义hook未加 `use` 前缀	遵循命名约定

Quick Detection Patterns

快速检测模式

useEffect Abuse (Most Common Anti-Pattern)

useEffect 滥用（最常见的反模式）

typescript

// ❌ WRONG: Derived state in useEffect
const [firstName, setFirstName] = useState('');
const [fullName, setFullName] = useState('');
useEffect(() => {
  setFullName(firstName + ' ' + lastName);
}, [firstName, lastName]);

// ✅ CORRECT: Compute during render
const fullName = firstName + ' ' + lastName;

typescript

// ❌ WRONG: Event logic in useEffect
useEffect(() => {
  if (product.isInCart) showNotification('Added!');
}, [product]);

// ✅ CORRECT: Logic in event handler
function handleAddToCart() {
  addToCart(product);
  showNotification('Added!');
}

typescript

// ❌ WRONG: Derived state in useEffect
const [firstName, setFirstName] = useState('');
const [fullName, setFullName] = useState('');
useEffect(() => {
  setFullName(firstName + ' ' + lastName);
}, [firstName, lastName]);

// ✅ CORRECT: Compute during render
const fullName = firstName + ' ' + lastName;

typescript

// ❌ WRONG: Event logic in useEffect
useEffect(() => {
  if (product.isInCart) showNotification('Added!');
}, [product]);

// ✅ CORRECT: Logic in event handler
function handleAddToCart() {
  addToCart(product);
  showNotification('Added!');
}

React 19 Hook Mistakes

React 19 Hook 使用错误

typescript

// ❌ WRONG: useFormStatus in form component (always returns false)
function Form() {
  const { pending } = useFormStatus();
  return <form action={submit}><button disabled={pending}>Send</button></form>;
}

// ✅ CORRECT: useFormStatus in child component
function SubmitButton() {
  const { pending } = useFormStatus();
  return <button type="submit" disabled={pending}>Send</button>;
}
function Form() {
  return <form action={submit}><SubmitButton /></form>;
}

typescript

// ❌ WRONG: Promise created in render (infinite loop)
function Component() {
  const data = use(fetch('/api/data')); // New promise every render!
}

// ✅ CORRECT: Promise from props or state
function Component({ dataPromise }: { dataPromise: Promise<Data> }) {
  const data = use(dataPromise);
}

typescript

// ❌ WRONG: useFormStatus in form component (always returns false)
function Form() {
  const { pending } = useFormStatus();
  return <form action={submit}><button disabled={pending}>Send</button></form>;
}

// ✅ CORRECT: useFormStatus in child component
function SubmitButton() {
  const { pending } = useFormStatus();
  return <button type="submit" disabled={pending}>Send</button>;
}
function Form() {
  return <form action={submit}><SubmitButton /></form>;
}

typescript

// ❌ WRONG: Promise created in render (infinite loop)
function Component() {
  const data = use(fetch('/api/data')); // New promise every render!
}

// ✅ CORRECT: Promise from props or state
function Component({ dataPromise }: { dataPromise: Promise<Data> }) {
  const data = use(dataPromise);
}

State Mutation Detection

状态修改检测

typescript

// ❌ WRONG: Mutations (no re-render)
items.push(newItem);
setItems(items);

arr[i] = newValue;
setArr(arr);

// ✅ CORRECT: Immutable updates
setItems([...items, newItem]);
setArr(arr.map((x, idx) => idx === i ? newValue : x));

typescript

// ❌ WRONG: Mutations (no re-render)
items.push(newItem);
setItems(items);

arr[i] = newValue;
setArr(arr);

// ✅ CORRECT: Immutable updates
setItems([...items, newItem]);
setArr(arr.map((x, idx) => idx === i ? newValue : x));

TypeScript Red Flags

TypeScript 危险信号

typescript

// ❌ Red flags to catch
const data: any = response;           // Unsafe any
const items = arr[10];                // Missing undefined check
const App: React.FC<Props> = () => {}; // Discouraged pattern

// ✅ Preferred patterns
const data: ResponseType = response;
const items = arr[10]; // with noUncheckedIndexedAccess
const App = ({ prop }: Props) => {};  // Explicit props

typescript

// ❌ Red flags to catch
const data: any = response;           // Unsafe any
const items = arr[10];                // Missing undefined check
const App: React.FC<Props> = () => {}; // Discouraged pattern

// ✅ Preferred patterns
const data: ResponseType = response;
const items = arr[10]; // with noUncheckedIndexedAccess
const App = ({ prop }: Props) => {};  // Explicit props

Review Workflow

评审工作流程

Scan for critical issues first - Check for the patterns in "Critical (Block Merge)" section
Check React 19 usage - See react19-patterns.md for new API patterns
Evaluate state management - Is state colocated? Server state vs client state separation?
Assess TypeScript safety - Generic components, discriminated unions, strict config
Review for maintainability - Component size, hook design, folder structure

优先扫描严重问题 - 检查「严重（阻止合并）」部分中的模式
检查React 19使用情况 - 查看 react19-patterns.md 了解新API模式
评估状态管理 - 状态是否就近放置？服务端状态与客户端状态是否分离？
评估TypeScript安全性 - 泛型组件、区分联合类型、严格配置
评审可维护性 - 组件大小、hook设计、文件夹结构

Reference Documents

参考文档

For detailed patterns and examples:

react19-patterns.md - React 19 new hooks (useActionState, useOptimistic, use), Server/Client Component boundaries
antipatterns.md - Comprehensive anti-pattern catalog with fixes
checklist.md - Full code review checklist for thorough reviews

如需详细模式和示例：

react19-patterns.md - React 19新hook（useActionState、useOptimistic、use）、服务端/客户端组件边界
antipatterns.md - 包含修复方案的全面反模式目录
checklist.md - 用于全面评审的完整代码评审清单

State Management Quick Guide

状态管理快速指南

Data Type	Solution
Server/async data	TanStack Query (never copy to local state)
Simple global UI state	Zustand (~1KB, no Provider)
Fine-grained derived state	Jotai (~2.4KB)
Component-local state	useState/useReducer
Form state	React 19 useActionState

数据类型	解决方案
服务端/异步数据	TanStack Query（切勿复制到本地状态）
简单全局UI状态	Zustand（约1KB，无需Provider）
细粒度派生状态	Jotai（约2.4KB）
组件本地状态	useState/useReducer
表单状态	React 19 useActionState

TanStack Query Anti-Pattern

TanStack Query 反模式

typescript

// ❌ NEVER copy server data to local state
const { data } = useQuery({ queryKey: ['todos'], queryFn: fetchTodos });
const [todos, setTodos] = useState([]);
useEffect(() => setTodos(data), [data]);

// ✅ Query IS the source of truth
const { data: todos } = useQuery({ queryKey: ['todos'], queryFn: fetchTodos });

typescript

// ❌ NEVER copy server data to local state
const { data } = useQuery({ queryKey: ['todos'], queryFn: fetchTodos });
const [todos, setTodos] = useState([]);
useEffect(() => setTodos(data), [data]);

// ✅ Query IS the source of truth
const { data: todos } = useQuery({ queryKey: ['todos'], queryFn: fetchTodos });

TypeScript Config Recommendations

TypeScript 配置建议

json

{
  "compilerOptions": {
    "strict": true,
    "noUncheckedIndexedAccess": true,
    "noImplicitReturns": true,
    "exactOptionalPropertyTypes": true
  }
}

noUncheckedIndexedAccess

is critical - it catches

arr[i]

returning undefined.

json

{
  "compilerOptions": {
    "strict": true,
    "noUncheckedIndexedAccess": true,
    "noImplicitReturns": true,
    "exactOptionalPropertyTypes": true
  }
}

noUncheckedIndexedAccess

至关重要 - 它能捕获

arr[i]

返回undefined的情况。

Immediate Red Flags

立即标记的危险信号

When reviewing, flag these immediately:

Pattern	Problem	Fix
`eslint-disable react-hooks/exhaustive-deps`	Hides stale closure bugs	Refactor logic
Component defined inside component	Remounts every render	Move outside
`useState(undefined)` for inputs	Uncontrolled warning	Use empty string
`React.FC` with generics	Generic inference breaks	Use explicit props
Barrel files ( `index.ts` ) in app code	Bundle bloat, circular deps	Direct imports

评审时，需立即标记以下模式：

模式	问题	修复方案
`eslint-disable react-hooks/exhaustive-deps`	隐藏闭包过时bug	重构逻辑
组件内部定义组件	每次渲染都会重新挂载	移到外部
输入框使用 `useState(undefined)`	非受控警告	使用空字符串
带泛型的 `React.FC`	泛型推断失效	使用显式props
应用代码中的桶文件（ `index.ts` ）	包体积膨胀、循环依赖	直接导入