import React, {useState,useEffect} from 'react';
import ReactDOM from 'react-dom';
import reportWebVitals from './reportWebVitals';
function AppTwo(props){
const [state, setState] = React.useState("initial value");
useEffect(() => {
console.log(`useEffect: ${state}`);
},[state]);
setState("updated value");
console.log(state);
return `<h1>${state}</h1>`;
}
ReactDOM.render(
<>
<AppTwo />
</>,
document.getElementById('root')
);
Error: Too many re-renders. React limits the number of renders to prevent an infinite loop.
Don't call setState inside of the component body. It will update every time the component re-renders. That's why you are getting an infinite loop of state updates.
WORKS!
import React, {useState,useEffect} from 'react';
import ReactDOM from 'react-dom';
import reportWebVitals from './reportWebVitals';
function AppTwo(props){
const [state, setState] = React.useState("initial value");
useEffect(() => {
console.log(`useEffect: ${state}`);
// document.getElementById('btn').innerHTML = `<h1>State: ${state}</h1>`;
},[state]);
console.log(state);
return (
<>
<h1>State: {state}</h1>
<button id="btn" onClick={() => {setState('updated value')}}>
click
</button>
</>
)
}
ReactDOM.render(
<>
<AppTwo />
</>,
document.getElementById('root')
);