Functional component:

const handleFocus = (event) => event.target.select();const Input = (props) => <input type="text" value="Some something" onFocus={handleFocus} />

ES6 class component:

class Input extends React.Component {    handleFocus = (event) => event.target.select();    render() {        return (            <input type="text" value="Some something" onFocus={this.handleFocus} />        );    }}

React.createClass:

React.createClass({    handleFocus: function(event) {      event.target.select();    },    render: function() {      return (        <input type="text" value="Some something" onFocus={this.handleFocus} />      );    },})

Thanks, I appreciate it. I did it so:

var input = self.refs.value.getDOMNode();            input.focus();            input.setSelectionRange(0, input.value.length);

Another Way Functional Component with useRefHook:

const inputEl = useRef(null);function handleFocus() {  inputEl.current.select();}<input  type="number"  value={quantity}  ref={inputEl}  onChange={e => setQuantityHandler(e.target.value)}  onFocus={handleFocus}/>