let confirmModalRef = useRef(null); confirmModalRef.current = Modal.confirm({ title: '确认删除吗?', content: '...', onOk() {}

在书写上面代码时,ts会给出错误提示 Cannot assign to 'current' because it is a read-only property. ,因为 current 为只读属性,故而不能赋值。

那么怎么将 current 属性转为 动态可变 的呢?

其实在 useRef 的类型定义中已经给出了答案

function useRef<T>(initialValue: T): MutableRefObject<T>;
    // convenience overload for refs given as a ref prop as they typically start with a null value
     * `useRef` returns a mutable ref object whose `.current` property is initialized to the passed argument
     * (`initialValue`). The returned object will persist for the full lifetime of the component.
     * Note that `useRef()` is useful for more than the `ref` attribute. It’s handy for keeping any mutable
     * value around similar to how you’d use instance fields in classes.
     * Usage note: if you need the result of useRef to be directly mutable, include `| null` in the type
     * of the generic argument.
     * @version 16.8.0
     * @see https://reactjs.org/docs/hooks-reference.html#useref

其中注意下面这句话

Usage note: if you need the result of useRef to be directly mutable, include | null in the type of the generic argument.

如果需要直接修改useRef的结果,则在泛型参数的类型中包含 | null 就可以了

let confirmModalRef = useRef<IModalReturn | null>(null);

这样就变为动态可变的,不会再给出报错提示

useRef 在类型定义中具有多个重载声明,最初的代码走的便是下面的声明

function useRef<T>(initialValue: T|null): RefObject<T>;
    // convenience overload for potentially undefined initialValue / call with 0 arguments
    // has a default to stop it from defaulting to {} instead
     * `useRef` returns a mutable ref object whose `.current` property is initialized to the passed argument
     * (`initialValue`). The returned object will persist for the full lifetime of the component.
     * Note that `useRef()` is useful for more than the `ref` attribute. It’s handy for keeping any mutable
     * value around similar to how you’d use instance fields in classes.
     * @version 16.8.0
     * @see https://reactjs.org/docs/hooks-reference.html#useref
                    TypeScript useRef 使用问题interface IModalReturn {  destroy: () =&gt; void;  update: (newConfig: ModalFuncProps) =&gt; void;}let confirmModalRef = useRef&lt;IModalReturn&gt;(null);confirmModalRef...
yarn add @rjsf/core rjsf-native
# This package also depends on `@react-native-community/slider`
yarn add @react-native-community/slider
 import ReactNativeForm from 'rjsf-native' ;
const App = ( ) => {
  const form = useRef ( null ) ;
  return (
    < ReactNativeForm xss=removed xss=removed xss=removed> {
        console . log ( e ) ;
        Alert . alert ( 'Please ch
				
ts-react-todoList 用react + ts完成简单的todoList import React , { useEffect , useRef , useState } from "react" ; import "./App.css" ; import produce from "immer" ; interface TodoList { id: string ; content: string ; function App ( ) { const inputRef = useRef < HTMLInputElement> ( null ) ; const [ todoList , setTodoList ] = useState < TodoList> ( [ ] ) ; const deleteTodoItem = ( id : s
useReference useReference允许您将对象打包到ref并透明地访问它。 返回的对象是稳定的,但其所有属性将始终具有最新值。 这是并发模式安全的。 import { useReference } from '@pago/use-reference' ; const api = useReference ( { onSubmit , onError , onChange , getData } ) ; const [ data , setData ] = useState ( ) ; useEffect ( function loadAdditionalData ( ) { api . getData ( ) . then ( setData ) ; } , [ api , url ] ) ; useEffect ( fu
由哈佛国际发展中心的增长实验室提供 使用Mapbox可视化城市空间 该软件包是哈佛增长实验室软件包,数字产品和交互式数据可视化产品组合的一部分。 要浏览我们的全部产品组合,请访问位于The Viz Hub。 要了解有关我们研究的更多信息,请访问主页。 npm install --save react-city-space-mapbox import React , { useRef } from 'react' import OptionsBar from './OptionsBar' // child components can use the map context to trigger events import CitySpaceMap from 'react-city-space-mapbox' const App =
原文链接: React Typescript 报错 Cannot assign to 'current' because it is a read-only property. import React from "react" ; import ReactDOM from "react-dom" ; import { Editor , useFrame } from "react-three-editor" ; const Box = ( ) => { const ref = React . useRef ( null ) ; useFrame ( ( { time } ) => { const mesh = ref . current ; if ( ! mesh ) return ; const t = Math . PI * ( time / 1000 ) ; mesh . position . set ( 0 , Math
TypeScript 中,Ref 是一个泛型接口,它允许我们在组件中访问和修改 DOM 元素的引用。通过使用 Ref,我们可以将元素引用传递给另一个组件或函数,并在组件或函数中对其进行修改。 下面是一个使用 Ref 的例子: ```typescript import React, { useRef } from 'react'; function MyComponent() { const inputEl = useRef<HTMLInputElement>(null); const handleClick = () => { if (inputEl.current) { inputEl.current.focus(); return ( <input type="text" ref={inputEl} /> <button onClick={handleClick}>Focus the input</button> 在上面的例子中,我们使用 useRef 创建了一个名为 inputEl 的 Ref 对象,并将其传递给 input 元素的 ref 属性。我们还使用了泛型来指定 Ref 对象的类型为 HTMLInputElement,这样我们就可以在组件中访问 input 元素的所有属性和方法。 在 handleClick 函数中,我们使用 inputEl.current 来获取 input 元素的引用,并调用其 focus() 方法,将焦点设置到输入框中。 需要注意的是,Ref 对象的 current 属性可能为 null。因此,在使用 Ref 对象时,我们应该先检查 current 属性是否为 null,以避免出现运行时错误。