MyCrypto/common/containers/Tabs/SendTransaction/components/UnitDropdown.jsx

// @flow
import React from 'react';

export default class UnitDropdown extends React.Component {
  props: {
    value: string,
    options: string[],
    onChange?: (value: string) => void
  };
  state: {
    expanded: boolean
  } = {
    expanded: false
  };

  render() {
    const { value, options, onChange } = this.props;
    const isReadonly = !onChange;

    return (
      <div className="input-group-btn">
        <a
          style={{ minWidth: 170 }}
          className="btn btn-default dropdown-toggle"
          onClick={this.onToggleExpand}
        >
          <strong>
            {value}<i className="caret" />
          </strong>
        </a>
        {this.state.expanded &&
          !isReadonly &&
          <ul className="dropdown-menu dropdown-menu-right">
            {options.map(o =>
              <li>
                <a
                  className={value === o ? 'active' : ''}
                  onClick={this.props.onChange}
                >
                  {o}
                </a>
              </li>
            )}
          </ul>}
      </div>
    );
  }

  onToggleExpand = () => {
    this.setState(state => {
      return {
        expanded: !state.expanded
      };
    });
  };
}