function LinkedCollection(records, opts) {
  utils.classCallCheck(this, LinkedCollection); // Make sure this collection has somewhere to store "added" timestamps

  Object.defineProperties(this, {
    _added: {
      value: {}
    },
    datastore: {
      writable: true,
      value: undefined
    }
  });
  Collection$1.call(this, records, opts); // Make sure this collection has a reference to a datastore

  if (!this.datastore) {
    throw utils.err("new ".concat(DOMAIN$9), 'opts.datastore')(400, 'DataStore', this.datastore);
  }
}
Extends {@link Collection}. Used by a {@link DataStore} to implement an
Identity Map.

```javascript
import {LinkedCollection} from 'js-data'
```

@class LinkedCollection
@extends Collection
@param {array} [records] Initial set of records to insert into the
collection. See {@link Collection}.
@param {object} [opts] Configuration options. See {@link Collection}.
@returns {Mapper}