参考Kotlin中的ObjectWrapper。 useRef用法 varref= React.useRef(88);ref.current +=1;// 该修改被应用到之后的视图渲染中!但是很明显,这种修改不会触发组件渲染return<div>{ref.current}</div>;
file=/src/use-ref.tsximport{ useEffect, useRef, useState }from"react";exportconstRefCount:React.FC=() =>{constref1 = useRef<HTMLButtonElement>(null);const[count, setCount] =useState(0);constrefCount = useRef<number>(count);constadd= () => {setCount(count +1); }; refCount.current= ...
useRef() gives us exactly that: 代码语言:javascript 复制 constsavedCallback=useRef();// { current: null } useRef() returns a plain object with a mutable current property that’s shared between renders.We can save the latest interval callback into it: 代码语言:javascript 复制 functioncallback...
setData]=useState({hits:[]});useEffect(()=>{constfetchData=async()=>{constresult=awaitaxios('https://hn.algolia.com/api/v1/search?query=redux',);setData(result.data);};fetchData();},[]);return(<ul>{data.hits.map(item=>(<li key={item.objectID}><a href={item.url}>{item...
(props); const ref = React.useRef(); React.useEffect(() => { instance.getRef = () => ref; instance.getProps = () => state; instance.updateState = (newState) => setState(Object.assign(state, newState)); }, []) return <C {...state} ref={ref}>{props.children ? render...
useRef:用于在函数组件中缓存任意值,包括 DOM 节点、计时器 ID 等; import React, { useRef, useEffect } from 'react'; function TextInput() { const inputRef = useRef(null); useEffect(() => { inputRef.current.focus(); }, []); return ( <div> <label> Name: <input type="text" ref={...
props const propsRef = useRef({}) const nextSkippedPropsRef = useRef({}) Object.keys(childProps) .filter(it => skips(it)) .forEach(key => { // 代理函数只会生成一次,其值始终不变 nextSkippedPropsRef.current[key] = nextSkippedPropsRef.current[key] || function skipNonRenderPropsProxy(....
importReact,{useRef}from'react';importReactDOMfrom'react-dom';importEditorfrom'@monaco-editor/react';functionApp(){consteditorRef=useRef(null);functionhandleEditorDidMount(editor,monaco){editorRef.current=editor;}functionshowValue(){alert(editorRef.current.getValue());}return(<><buttononClick={show...
example above, the component will rerender every time thereadyStateof the WebSocket changes, as well as when the WebSocket receives a message (which will changelastMessage).sendMessageis a memoized callback that will pass the message to the current WebSocket (referenced to internally withuseRef)...
loadMap 接收一个 Object ,key-value 分别为 key 以及对应的 loader,分别调用 load 方法,加载传入 Object 中所有 loader。 策略模式种的两种加载器已经分析完了,接下来就让我们看看核心的工厂方法 createLoadableComponent: function createLoadableComponent(loadFn, options) { // 必须传入 loading 组件 if (!