Useref in react

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>
    </>
  );
}

Source: reactjs.org

UseReducer

const initialState = {count: 0};

function reducer(state, action) {
  switch (action.type) {
    case 'increment':
      return {count: state.count + 1};
    case 'decrement':
      return {count: state.count - 1};
    default:
      throw new Error();
  }
}

function Counter() {
  const [state, dispatch] = useReducer(reducer, initialState);
  return (
    <>
      Count: {state.count}
      <button onClick={() => dispatch({type: 'decrement'})}>-</button>
      <button onClick={() => dispatch({type: 'increment'})}>+</button>
    </>
  );
}

Source: reactjs.org

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.

Source: reactjs.org

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>
    </>
  );
}

Source: reactjs.org

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>
    </>
  );
}

Source: reactjs.org

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>;
}

Source: dmitripavlutin.com

Similar codes

0 vote268 views1 answer
Rn push notification No task registered for key ReactNativeFirebaseMessagingHeadlessTask
Javascript React
1 vote281 views2 answers
Hide react source
Javascript React
17 votes273 views3 answers
React canvas clear
Javascript React
0 vote273 views1 answer
How to creacte react component
Javascript React
1 vote269 views1 answer
How to detect onend reach of scrollview in react native
Javascript React
0 vote268 views1 answer
Icomoon react native
Javascript React
0 vote223 views1 answer
Import pdfmake in react
Javascript React
0 vote271 views2 answers
React generate component command
Javascript React
0 vote260 views3 answers
Link react router dom
Javascript React
0 vote275 views1 answer
Sort by attribute in reactjs
Javascript React