react use ref code example

Example 1: 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>
    </>
  );
}

Example 2: react focus

const FocusDemo = () => {

    const [inputRef, setInputFocus] = useFocus()

    return (
        <> 
            <button onClick={setInputFocus} >
               FOCUS
            </button>
            <input ref={inputRef} />
        </>
    )

}

const useFocus = () => {
    const htmlElRef = useRef(null)
    const setFocus = () => {htmlElRef.current &&  htmlElRef.current.focus()}

    return [ htmlElRef, setFocus ] 
}

Example 3: react useref in useeffect

import React, { useEffect, useRef } from 'react';

const fooComponent = props => {
	const inputBtnRef = useRef(null);
  	useEffect(() => {
      //Add the ref action here
      inputBtnRef.current.focus();
    });
  
  	return (
      <div>
        <input
          type="text"
          ref={inputBtnRef} 
		/>
      </div>
    );
}

Example 4: react.createref()

class CustomTextInput extends React.Component {
  constructor(props) {
    super(props);
    // create a ref to store the textInput DOM element
    this.textInput = React.createRef();    this.focusTextInput = this.focusTextInput.bind(this);
  }

  focusTextInput() {
    // Explicitly focus the text input using the raw DOM API
    // Note: we're accessing "current" to get the DOM node
    this.textInput.current.focus();  }

  render() {
    // tell React that we want to associate the <input> ref
    // with the `textInput` that we created in the constructor
    return (
      <div>
        <input
          type="text"
          ref={this.textInput} />        <input
          type="button"
          value="Focus the text input"
          onClick={this.focusTextInput}
        />
      </div>
    );
  }
}

Example 5: when to use react ref

WHEN TO USE REACT'S REF ATTRIBUTE?
But it is not always a good idea to use the ref attribute. The general rule of thumb is to avoid it. The official React documentation mentions three occasions where you can use it because you have no other choice.

Managing focus, text selection, or media playback.
Integrating with third-party DOM libraries.
Triggering imperative animations.

Example 6: refs react js

class Lesson9Refs extends Component {

    onAddProduct = () => {
        alert(this.refs.productname.value);
    }
    
    
    return (

            <div>

                <div className="container">
                    <div class="card mt-10">
                        <div class="card-header">
                            Featured
                        </div>
                        <div class="card-body">
                          
                            <label> Product Name: </label>
                            <input type='text' className="form-control" ref="productname" />  

                            <button type="submit" className="btn btn-primary" onClick={ this.onAddProduct } >
                                Add Product
                            </button>

                        </div>
                    </div>
                    <div className="row mt-10">
                        { elements }
                    </div>
                </div>
            </div>
        );

    }
}

export default Lesson9Refs;