content: import React from 'react';
  import PropTypes from 'prop-types';
  import classNames from 'classnames';
  
  class ToolbarButton extends React.Component {
    render() {
      const className = classNames(
        'toolbar-button',
        { 'toolbar-button-expand': this.props.expand },
        { 'toolbar-button-selected': this.props.selected }
      );
  
      return (
        <div className={className} onClick={this.props.onClick}>
          {this.props.children}
        </div>
      );
    }
  }
  
  ToolbarButton.propTypes = {
    expand: PropTypes.bool,
    onClick: PropTypes.func.isRequired,
    children: PropTypes.any.isRequired,
  };
  
  export default ToolbarButton;
  