Useref 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 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

  const inputEl = useRef(null);

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

Similar codes

1 vote262 views1 answer
Input type email react js-validation
Javascript React
0 vote226 views1 answer
Rendering an array in react
Javascript React
2 votes269 views2 answers
React get url querystring
Javascript React
0 vote265 views1 answer
Valueof in react native
Javascript React
0 vote279 views2 answers
This.webview.postmessage is not a function reactnative
Javascript React
0 vote265 views3 answers
Unexpected template string expression no-template-curly-in-string react
Javascript React
1 vote295 views3 answers
How to decode jwt token in react
Javascript React
2 votes267 views2 answers
React native scrollview detect end
Javascript React
4 votes261 views4 answers
React background gradient
Javascript React
2 votes215 views6 answers
React font-awesome
Javascript React