import Popover from 'react-simple-popover'; import React, { Component } from 'react';  class PopoverDemo extends Component {   constructor(props) {     super(props);     this.state = {       open: false     };   }    handleClick = (e) => {     this.setState({open: !this.state.open});   }    handleClose = (e) => {     this.setState({open: false});   }    render() {     return (       <div>         <a           href="#"           className="button"           ref={(node) => { this.target = node }}           onClick={this.handleClick}>Popover</a>         <Popover           placement='left'           container={this}           target={this.target}           show={this.state.open}           onHide={this.handleClose} >           <p>This is popover</p>         </Popover>       </div>     );   } }