'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
});