insomnia/app/components/base/Dropdown.js

import React, {Component, PropTypes} from 'react'
import classnames from 'classnames'

class Dropdown extends Component {
  constructor (props) {
    super(props);
    this.state = {
      open: false
    };
  }

  _handleClick (e) {
    e.preventDefault();
    this.setState({open: !this.state.open});
  }

  render () {
    const className = classnames(
      'dropdown',
      this.props.className,
      {'dropdown--open': this.state.open},
      {'dropdown--right': this.props.right}
    );

    return (
      <div className={className} onClick={this._handleClick.bind(this)}>
        {this.props.children}
        <div className="dropdown__backdrop"></div>
      </div>
    )
  }
}

Dropdown.propTypes = {
  right: PropTypes.bool
};

export default Dropdown;