useRef
/*
A common use case is to access a child imperatively:
*/
function TextInputWithFocusButton() {
const inputEl = useRef(null);
const onButtonClick = () => {
// `current` points to the mounted text input element
inputEl.current.focus();
};
return (
<>
<input ref={inputEl} type="text" />
<button onClick={onButtonClick}>Focus the input</button>
</>
);
}useref in functional component
import React, { useRef } from 'react';
function TextInputWithFocusButton() {
const inputEl = useRef(null);
const onButtonClick = () => {
// `current` points to the mounted text input element
inputEl.current.focus();
};
return (
<>
<input ref={inputEl} type="text" />
<button onClick={onButtonClick}>Focus the input</button>
</>
);
}useRef() in react
function TextInputWithFocusButton() {
const inputEl = useRef(null);
const onButtonClick = () => {
// `current` points to the mounted text input element
inputEl.current.focus();
};
return (
<>
<input ref={inputEl} type="text" />
<button onClick={onButtonClick}>Focus the input</button>
</>
);
}what does useref do react
const refContainer = useRef(initialValue);
//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.useRef
import React, { useState, useEffect, useRef } from 'react'
import isDeepEqual from 'fast-deep-equal/react'import { getPlayers } from '../api'
import Players from '../components/Players'
const Team = ({ team }) => {
const [players, setPlayers] = useState([])
const teamRef = useRef(team)
if (!isDeepEqual(teamRef.current, team)) { teamRef.current = team }
useEffect(() => {
if (team.active) {
getPlayers(team).then(setPlayers)
}
}, [teamRef.current])
return <Players team={team} players={players} />
}useref in react
import { useRef } from 'react';
function LogButtonClicks() {
const countRef = useRef(0);
const handle = () => {
countRef.current++; console.log(`Clicked ${countRef.current} times`);
};
console.log('I rendered!');
return <button onClick={handle}>Click me</button>;
}Copyright © 2021 Codeinu
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