old_contents: 'use strict';
  
  function parse(json) {
      try {
          return JSON.parse(json);
      } catch (e) {
          return undefined;
      }
  }
  
  function stringify(object) {
      try {
          return JSON.stringify(object);
      } catch (e) {
          return "null";
      }
  }
  
  module.exports = {
      parse: parse,
      stringify: stringify,
  };
  
new_contents: 'use strict';
  
  function parse(json) {
      try {
          return JSON.parse(json);
      } catch (e) {
          return undefined;
      }
  }
  
  function stringify(object) {
      try {
          if (object === undefined) throw undefined;
          return JSON.stringify(object);
      } catch (e) {
          return "null";
      }
  }
  
  module.exports = {
      parse: parse,
      stringify: stringify,
  };
  
subject: fix stringification of undefined