text: 'use strict';
  
  var Type = require('../type');
  
  var _hasOwnProperty = Object.prototype.hasOwnProperty;
  
  function resolveYamlSet(data) {
    if (data === null) return true;
  
    var key, object = data;
  
    for (key in object) {
      if (_hasOwnProperty.call(object, key)) {
        if (object[key] !== null) return false;
      }
    }
  
    return true;
  }
  
  function constructYamlSet(data) {
    return data !== null ? data : {};
  }
  
  module.exports = new Type('tag:yaml.org,2002:set', {
    kind: 'mapping',
    resolve: resolveYamlSet,
    construct: constructYamlSet
  });
  