packages/skygear-core/lib/reference.js

/**
 * Copyright 2015 Oursky Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import Record from './record';

/**
 * Reference
 *
 * A model representing a record reference in Skygear record.
 */
export default class Reference {

  /**
   * Constructs a new Reference object.
   *
   * @param {Record|String} attrs - the referenced record or record id
   */
  constructor(attrs) {
    var id;
    if (typeof attrs === 'string') {
      id = attrs;
    } else {
      id = attrs.$id;
      if (!id) {
        id = attrs.id;
      }
    }

    if (!id) {
      throw new Error('Empty record id');
    }

    // parse solely to test for string id validity
    Record.parseID(id);

    this._id = id;
  }

  /**
   * ID of the referenced record
   *
   * @type {String}
   */
  get id() {
    return this._id;
  }

  /**
   * Serializes Reference to a JSON object.
   *
   * @return {Object} the JSON object
   */
  toJSON() {
    return {
      $id: this._id,
      $type: 'ref'
    };
  }
}