text: const include = (types) => types
      ? { variables: types }
      : {};
  
  const sanitize = variables => {
      const keys = Object.keys(variables);
      const variablesParams = keys.map(key => `${ key }:${ variables[key] }`);
  
      return JSON.stringify(variablesParams.join(', '), ' ', 4)
          .replace(/(?:"|')/g, '');
  };
  
  const sift = ({
      inputs,
      variables
  }) => Object.keys(inputs).reduce((accumulator, inputVariable) => {
      accumulator[`$${ inputVariable }`] = variables[`$${ inputVariable }`];
  
      return accumulator;
  }, {});
  
  module.exports = {
      include,
      sanitize,
      sift
  };
  