text: import React, { Component } from 'react';
  import PropTypes from 'prop-types';
  
  import { Dropdown } from 'components/elements';
  
  const options = [
    { value: 'is null', label: 'is null' },
    { value: 'is not null', label: 'is not null' }
  ];
  
  export default class CheckExistence extends Component {
    handleChange = event => {
      const { index, updateAppliedModifier } = this.props;
      const selectedOption = options.find(option => option.value === event.target.value);
      updateAppliedModifier(index, { value: selectedOption ? selectedOption.value : null });
    }
  
    render() {
      const { value } = this.props;
  
      return (
        <div className="modifier">
          <Dropdown
            className="field-input field-input-lg"
            id="check-existence"
            label="Check existence"
            onChange={this.handleChange}
            options={options}
            value={value}
          />
        </div>
      );
    }
  }
  
  CheckExistence.propTypes = {
    index: PropTypes.number.isRequired,
    updateAppliedModifier: PropTypes.func.isRequired,
    value: PropTypes.string
  };
  