import{useState}from'react';// 👇️ should take props object and not setCount directly// ⛔️ Uncaught TypeError: setCount is not a functionfunctionChild(setCount){return(<div><buttononClick={()=>setCount(current => current + 1)}> Click</button></div>); }exportdefaultfunctionApp...
当我们为元素的onClick属性传递一个值,但是该值却不是函数时,会产生"ExpectedonClicklistener to be a function"报错。为了解决该报错,请确保只为元素的onClick属性传递函数。 这里有个例子来展示错误是如何发生的。 // App.jsconstApp= () => {// ⛔️ Warning: Expected `onClick` listener to be a ...
The error “ Expected onClick listener to be a functiononClick” occurs whenwe pass a value that is not a function to the element’s attribute. To fix the error, make sure that you pass only functions to the element’sattribute.onClick constApp=()=>{// ⛔️ Warning: Expected `on...
const [state, dispatch]=useReducer(reducer, initialState);return(<>Count: {state.count}<button onClick={() => dispatch({ type: "increment" })}>+</button> <button onClick={() => dispatch({ type: "decrement" })}>-</button> </>); }; exportdefaultCounter; 四、事件处理 1. Event ...
functionExample() {const[count,setCount]=React.useState(0)letotherStateif(count>0) {React.useEffect(()=>{console.log('count',count)})}constincrement=()=>setCount((c)=>c+1)return<buttononClick={increment}>{count}</button>} The point is that ourExamplecomponent is calling a hook condit...
function Toolbar(props) { return ( <div> <ThemedButton /> </div> ); } class ThemedButton extends React.Component { // Assign a contextType to read the current theme context. // React will find the closest theme Provider above and use its value. ...
(ref.current.checked){console.log('✅ Checkbox is checked');}else{console.log('⛔️ Checkbox is NOT checked');}};return(<div><label htmlFor="subscribe"><input ref={ref}type="checkbox"id="subscribe"name="subscribe"/>Subscribe</label><br/><button onClick={handleClick}>Click</...
function MyButton() { function handleClick() { alert('You clicked me!'); } return ( <button onClick={handleClick}> Click me </button> ); } Notice how onClick={handleClick} has no parentheses at the end! Do not call the event handler function: you only need to pass it down. Re...
<div className="mineBox" id={this.props.id} onDoubleClick={this.props.onDoubleClick} onClick={this.props.onClick}></div> ) } }); var MineRow = React.createClass({ render: function(){ var width = this.props.width, row = []; ...
importReact,{Fragment,useReducer,useEffect,useHistory}from'react';exportconstUserDetail=()=>{consthistory=useHistory();functiononClickEditHandle(){history.push(userEditHistory(state.user.id))}return(<buttononClick={onClickEditHandle}/>)}