react+ts必备：react中常用的ts类型大全

 const MyArrayComponent = () => (Array(5).fill(<div/>) as any) as JSX.Element

// 函数  React.FC<Props>;   
// 类    React.Component<Props,state>

type SelectProps<T> = {items: T[]}; 
class Select<T> extends React.Component<SelectProps<T>, {}> { 
   //...
const Form = () => <Select<string> items={['a','b']}>
 

function foo<T>(x:T): T{    
 return x 
// 注：如果是箭头函数需要用extends提示编辑器这是个泛型 
// const foo = <T extends Record<string,unknow>>() => {}
 

class MyAwesomeComponent extends React.Component {   
  render() {     
    return <div>Hello</div>;   
const foo: React.ReactElement<MyAwesomeComponent> = <MyAwesomeComponent />; // Okay 
const bar: React.ReactElement<MyAwesomeComponent> = <NotMyAwesomeComponent />; // Error
 

const [user,setUser] = React.useState<IUser | null>(null);  
const [user,setUser] = React.useState<IUser>({} as IUser)

import { Reducer } from 'redux'; 
export function reducer:  Reducer<AppState, Action>() {
}

// 如果可以的话尽量使用的类型具体点 
// 比如使用HTMLDivElement 就比HTMLElement好很多，比Element好更多 
function Foo(){ 
  const divRef = useRef<HTMLDivElement>(null); 
  return <div>etc<div/> 
}

1.as
2.泛型注解(React的jsx里用不了)
3.去除null或undefined的非空断言

function fn(){
  return ['1',false] 
type AType = string[] 
let a:AType = fn() // error 
// 解决办法： 
// 1.将其变为 return ['1',false] as any[] 或者 return ['1',false] as string[]，如果是只读的可以 as const 
// 2. type Atype = (string | boolean)[],但已不符合实际意义 
// 3. react团队推荐自定义钩子return两个以上的值时可以使用对象

type Theme = 'light' | 'dark'
const TeemeContext = React.createContext<Theme>('dark')
// 创建{}用断言  const Context = React.createContext({} as ContextState);
const sampleAppContext: TeemeContext = 'light';
export const App = () => (
  <AppCtx.Provider value={sampleAppContext}>...</AppCtx.Provider>
// 如果想创建默认值为null或undefined可以React.createContext<string>(undefined!)，不然在使用.时
// 会报没有相关api可以调用,但这样失去了类型安全，或者可以使用一个helper函数来帮助我们创建，让我们不再考虑undeined
// 的情况
function createCtx<A extends {} | null>() {
  const ctx = React.createContext<A | undefined>(undefined);
  function useCtx() {
    const c = React.useContext(ctx);
    if (c === undefined)
      throw new Error("useCtx must be inside a Provider with a value");
    return c;
  return [useCtx, ctx.Provider] as const; // 'as const' makes TypeScript infer a tuple
// Usage:
// We still have to specify a type, but no default!
export const [useCurrentUserName, CurrentUserProvider] = createCtx<string>();
function EnthusasticGreeting() {
  const currentUser = useCurrentUserName();
  return <div>HELLO {currentUser.toUpperCase()}!</div>;
function App() {
  return (
    <CurrentUserProvider value="Anders">
      <EnthusasticGreeting />
    </CurrentUserProvider>
// 整合useContext，createContext，useState为一体
export function createCtx<A>(defaultValue: A) {
  type UpdateType = React.Dispatch<
    React.SetStateAction<typeof defaultValue>
  const defaultUpdate: UpdateType = () => defaultValue;
  const ctx = React.createContext({
    state: defaultValue,
    update: defaultUpdate,
  function Provider(props: React.PropsWithChildren<{}>) {
    const [state, update] = React.useState(defaultValue);
    return <ctx.Provider value={{ state, update }} {...props} />;
  return [ctx, Provider] as const; // alternatively, [typeof ctx, typeof Provider]
// usage
const [ctx, TextProvider] = createCtx("someText");
export const TextContext = ctx;
export function App() {
  return (
    <TextProvider>
      <Component />
    </TextProvider>
export function Component() {
  const { state, update } = React.useContext(TextContext);
  return (
    <label>
      {state}
      <input type="text" onChange={(e) => update(e.target.value)} />
    </label>
//更好的createContextApi
https://gist.github.com/sw-yx/f18fe6dd4c43fddb3a4971e80114a052

export interface MyInputHandles {
    focus(): void;
const MyInput: RefForwardingComponent<MyInputHandles, MyInputProps> = (props, ref) => {
    const inputRef = useRef<HTMLInputElement>(null);
    useImperativeHandle(ref, () =>({
        focus: () => {
            if(inputRef.current) {
                inputRef.current.focus();
    return <Input {...props} ref={inputRef}>    
export default forwardRef(MyInput)
 

 pointer: number

static getDerivedStateFromProps(props:Props, state:State): Partial<State> | null {
}

static getDerivedStateFromProps(props:Props, state:State): Partial<State> | null {
}

​const GreetComponent = ({ name, age }: {name:string, age:25}) => (
  <div>{`Hello, my name is ${name}, ${age}`}</div>
type ComponentProps<T> = T extends
  | React.ComponentType<infer P>
  | React.Component<infer P>
  ? JSX.LibraryManagedAttributes<T, P>
  : never;
const TestComponent = (props: ComponentProps<typeof GreetComponent>) => {
  return <h1 />;

type AppProps = {
  message: string;
  count: number;
  disabled: boolean;
  /** array of a type! */
  names: string[];
  /** string literals to specify exact string values, with a union type to join them together */
  status: "waiting" | "success";
  /** any object as long as you dont use its properties (NOT COMMON but useful as placeholder) */
  obj: object;
  obj2: {}; // almost the same as `object`, exactly the same as `Object`
  /** an object with any number of properties (PREFERRED) */
  obj3: {
    id: string;
    title: string;
  /** array of objects! (common) */
  objArr: {
    id: string;
    title: string;
  /** a dict object with any number of properties of the same type */
  dict1: {
    [key: string]: MyTypeHere;
  dict2: Record<string, MyTypeHere>; // equivalent to dict1
  /** any function as long as you don't invoke it (not recommended) */
  onSomething: Function;
  /** function that doesn't take or return anything (VERY COMMON) */
  onClick: () => void;
  /** function with named prop (VERY COMMON) */
  onChange: (id: number) => void;
  /** alternative function type syntax that takes an event (VERY COMMON) */
  onClick(event: React.MouseEvent<HTMLButtonElement>): void;
  /** an optional prop (VERY COMMON!) */
  optional?: OptionalType;
};

 ​ ​
export declare interface AppProps {
  children1: JSX.Element; // bad, doesnt account for arrays
  children2: JSX.Element | JSX.Element[]; // meh, doesn't accept strings
  children3: React.ReactChildren; // despite the name, not at all an appropriate type; it is a utility
  children4: React.ReactChild[]; // better, accepts array children
  children: React.ReactNode; // best, accepts everything (see edge case below)，but {} as children is not supported
  functionChildren: (name: string) => React.ReactNode; // recommended function as a child render prop type
  style?: React.CSSProperties; // to pass through style props
  onChange?: React.FormEventHandler<HTMLInputElement>; // form events! the generic parameter is the type of event.target
  //  more info: https://react-typescript-cheatsheet.netlify.app/docs/advanced/patterns_by_usecase/#wrappingmirroring
  props: Props & React.ComponentPropsWithoutRef<"button">; // to impersonate all the props of a button element and explicitly not forwarding its ref
  props2: Props & React.ComponentPropsWithRef<MyButtonWithForwardRef>; // to impersonate all the props of MyButtonForwardedRef and explicitly forwarding its ref
​

// 1. 普通情况
class Comp extends React.Component<
  Props,
  ReturnType<typeof Comp["getDerivedStateFromProps"]>
  static getDerivedStateFromProps(props: Props) {}
// 2. 返回函数
type CustomValue = any;
interface Props {
  propA: CustomValue;
interface DefinedState {
  otherStateField: string;
type State = DefinedState & ReturnType<typeof transformPropsToState>;
function transformPropsToState(props: Props) {
  return {
    savedPropA: props.propA, // save for memoization
    derivedState: props.propA,
class Comp extends React.PureComponent<Props, State> {
  constructor(props: Props) {
    super(props);
    this.state = {
      otherStateField: "123",
      ...transformPropsToState(props),
  static getDerivedStateFromProps(props: Props, state: State) {
    if (isEqual(props.propA, state.savedPropA)) return null;
    return transformPropsToState(props);
}

// 如果不考虑性能的话，可以使用内联处理，注解将自动正确生成
const el = (
    <button onClick=(e=>{
        //...
// 如果需要在外部定义类型
handlerChange = (e: React.FormEvent<HTMLInputElement>): void => {
// 如果在=号的左边进行注解
handlerChange: React.ChangeEventHandler<HTMLInputElement> = e => {
// 如果在form里onSubmit的事件,React.SyntheticEvent,如果有自定义类型，可以使用类型断言
  ref={formRef}
  onSubmit={(e: React.SyntheticEvent) => {
    e.preventDefault();
    const target = e.target as typeof e.target & {
      email: { value: string };
      password: { value: string };
    const email = target.email.value; // typechecks!
    // etc...
    <label>
      Email:
      <input type="email" name="email" />
    </label>
    <input type="submit" value="Log in" />
</form>

AnimationEvent ： css动画事件
ChangeEvent：<input>， <select>和<textarea>元素的change事件
ClipboardEvent： 复制，粘贴，剪切事件
CompositionEvent：由于用户间接输入文本而发生的事件(例如，根据浏览器和PC的设置，如果你想在美国键盘上输入日文，可能会出现一个带有额外字符的弹出窗口)
DragEvent：在设备上拖放和交互的事件
FocusEvent: 元素获得焦点的事件
FormEvent: 当表单元素得失焦点/value改变/表单提交的事件
InvalidEvent: 当输入的有效性限制失败时触发(例如<input type="number" max="10">，有人将插入数字20)
KeyboardEvent: 键盘键入事件
MouseEvent： 鼠标移动事件
PointerEvent： 鼠标、笔/触控笔、触摸屏)的交互而发生的事件
TouchEvent： 用户与触摸设备交互而发生的事件
TransitionEvent： CSS Transition，浏览器支持度不高
UIEvent：鼠标、触摸和指针事件的基础事件。
WheelEvent: 在鼠标滚轮或类似的输入设备上滚动
SyntheticEvent：所有上述事件的基础事件。是否应该在不确定事件类型时使用
// 因为InputEvent在各个浏览器支持度不一样，所以可以使用KeyboardEvent代替

class CssThemeProvider extends React.PureComponent<Props> {
  private rootRef = React.createRef<HTMLDivElement>(); // like this
  render() {
    return <div ref={this.rootRef}>{this.props.children}</div>;
// 这样的forwardRef是可变的，可以在需要的时候给它赋值
type Props = { children: React.ReactNode; type: "submit" | "button" };
export type Ref = HTMLButtonElement;
export const FancyButton = React.forwardRef<Ref, Props>((props, ref) => (
  <button ref={ref} className="MyClassName" type={props.type}>
    {props.children}
  </button>
// 如果希望它不可变
// type Ref = HTMLButtonElement
// (props, ref: React.Ref<Ref>) =>
// 如果你希望抓取forwardRef组件的props，可以使用compoentPropsWithRef

// Class
const modalRoot = document.getElementById("modal-root") as HTMLElement;
// assuming in your html file has a div with id 'modal-root';
export class Modal extends React.Component {
  el: HTMLElement = document.createElement("div");
  componentDidMount() {
    modalRoot.appendChild(this.el);
  componentWillUnmount() {
    modalRoot.removeChild(this.el);
  render() {
    return ReactDOM.createPortal(this.props.children, this.el);
// hooks
import React, { useEffect, useRef } from "react";
import { createPortal } from "react-dom";
const modalRoot = document.querySelector("#modal-root") as HTMLElement;
const Modal: React.FC<{}> = ({ children }) => {
  const el = useRef(document.createElement("div"));
  useEffect(() => {
    // Use this in case CRA throws an error about react-hooks/exhaustive-deps
    const current = el.current;
    // We assume `modalRoot` exists with '!'
    modalRoot!.appendChild(current);
    return () => void modalRoot!.removeChild(current);
  }, []);
  return createPortal(children, el.current);
export default Modal;

//option1 ： 使用 react-error-boundary
//option2 :  自定义boundary component
import React, { Component, ErrorInfo, ReactNode } from "react";
interface Props {
  children: ReactNode;
interface State {
  hasError: boolean;
class ErrorBoundary extends Component<Props, State> {
  public state: State = {
    hasError: false
  public static getDerivedStateFromError(_: Error): State {
    // Update state so the next render will show the fallback UI.
    return { hasError: true };
  public componentDidCatch(error: Error, errorInfo: ErrorInfo) {
    console.error("Uncaught error:", error, errorInfo);
  public render() {
    if (this.state.hasError) {
      return <h1>Sorry.. there was an error</h1>;
    return this.props.children;
export default ErrorBoundary;

interface Admin {
  role: string;
interface User {
  email: string;
// Method 1: use `in` keyword
function redirect(user: Admin | User) {
  if ("role" in user) {
    // use the `in` operator for typeguards since TS 2.7+
    routeToAdminPage(user.role);
  } else {
    routeToHomePage(user.email);
// Method 2: custom type guard, does the same thing in older TS versions or where `in` isnt enough
function isAdmin(user: Admin | User): user is Admin {
  return (user as any).role !== undefined;
// Method ...: typeOf 和instanceof也可进行方便的类型保护

element.parentNode!.removeChild(element); // ! before the period
myFunction(document.getElementById(dialog.id!)!); // ! after the property accessing
let userID!: string; // definite assignment assertion... be careful!

type OrderID = string & { readonly brand: unique symbol };
type UserID = string & { readonly brand: unique symbol };
type ID = OrderID | UserID;
function OrderID(id: string) {
  return id as OrderID;
function UserID(id: string) {
  return id as UserID;
function queryForUser(id: UserID) {
  // ...
queryForUser(OrderID("foobar")); // Error, Argument of type 'OrderID' is not assignable 
// to parameter of type 'UserID'
// unique 是一个关键词
// unique T(其中T是任何类型)允许在任何位置使用类型，并且名义上用标记标记T，使来自该位置的T只能分配给结果类型。
// 它是制造它的每个符号的唯一结构。然后通过交集将其混合到参数类型中，从而生成所有有用的关系
// 译文: 唯一符号的当前行为优先于语法上完全唯一的符号，然而，如果符号的一个名义子类实际上是需要的，你可以写
// Unique (symbol)来获得一个名义上的品牌符号类型(或symbol & Unique unknown -这是完全相同的事情)。唯一
// 符号的行为方式就像锁定在特定声明中的符号，因此在收缩和控制流时具有特殊能力。名义上的品牌类型在使用上更灵活，
// 但不具有强大的控制流链接的主机声明
// https://github.com/microsoft/TypeScript/pull/33038
// 实例：
// type NormalizedPath = unique string;
// type AbsolutePath = unique string;
// type NormalizedAbsolutePath = NormalizedPath & AbsolutePath;
// declare function isNormalizedPath(x: string): x is NormalizedPath;
// declare function isAbsolutePath(x: string): x is AbsolutePath;
// declare function consumeNormalizedAbsolutePath(x: NormalizedAbsolutePath): void;
// const p = "/a/b/c";
// if (isNormalizedPath(p)) {
//     if (isAbsolutePath(p)) {
//         consumeNormalizedAbsolutePath(p);
//     }
// }

// 1.
function pickCard(x: { suit: string; card: number }[]): number;
function pickCard(x: number): { suit: string; card: number };
function pickCard(x): any {
  // implementation with combined signature
  // ...
// 2.
type pickCard = {
  (x: { suit: string; card: number }[]): number;
  (x: number): { suit: string; card: number };
  // no need for combined signature in this form
  // you can also type static properties of functions here eg `pickCard.wasCalled`
};

declare module 'use-untyped-hook' {
  export interface InputProps { ... }   // type declaration for prop
  export interface ReturnProps { ... } // type declaration for return props
  export default function useUntypedHook(
    prop: InputProps
    // ...
  ): ReturnProps;
}

import * as React from "react";
declare class SimpleSelect extends React.Component<SimpleSelectProps, any> {}
export interface SimpleSelectProps {
  autofocus?: boolean;
  cancelKeyboardEventOnSelection?: boolean;
  className?: string;
  createFromSearch?(items: OptionValue[], search: string): OptionValue;
  defaultValue?: OptionValue;
  delimiters?: [any];
  disabled?: boolean;
  // ...
export default SimpleSelect;

ConstructorParameters ：类构造函数参数类型的元组
Exclude：将一个类型从另一个类型排除
Extract：选择可分配给另一类型的子类型
InstanceType：从一个新类构造函数中获得的实例类型
NonNullable：从类型中排除空和未定义
Parameters：函数的形参类型的元组
Partial：使对象中的所有属性都是可选的
Readonly：将对象中的所有属性设置为只读
ReadonlyArray：创建给定类型的不可变数组
Pick：对象类型的一种子类型，包含其键的子集
Record：从键类型到值类型的映射
Required：使对象中的所有属性都是必需的
ReturnType：函数的返回类型

{