message: Fix typings on RecordKeyMap
diff: @@ -23,14 +23,14 @@ export class RecordKeyMap {
  /**
  * Return a key value given a model type, key name, and id.
  */
  - idToKey(type: string, keyName: string, idValue: string): string {
  + idToKey(type: string, keyName: string, idValue: string): string | undefined {
  return deepGet(this._idsToKeys, [type, keyName, idValue]);
  }
  /**
  * Return an id value given a model type, key name, and key value.
  */
  - keyToId(type: string, keyName: string, keyValue: string): string {
  + keyToId(type: string, keyName: string, keyValue: string): string | undefined {
  return deepGet(this._keysToIds, [type, keyName, keyValue]);
  }
  