@onehilltech/dab/lib/resolvers/ref.js

a complex data builder that uses simple definitions

/*
 * Copyright (c) 2018 One Hill Technologies, LLC
 *
 * 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.
 *
 */

const {
  isString,
  isFunction,
  isPlainObject
} = require ('lodash');

module.exports = function (value) {
  return function __dabRef () {
    return this.resolve (value).then (result => {
      if (result === undefined)
        return undefined;

      const idKey = this.opts.id || this.backend.getPrimaryKeyForPath (this.path);

      if (isString (result)) {
        const idPath = result + '.' + idKey;
        const id = this.get (idPath);

        if (isFunction (id))
          return undefined;

        return id;
      }
      else if (isPlainObject (result)) {
        return result[idKey];
      }
    });
  }
};