Function createQueryFieldIndex

core/queryIndex.ts:60–290

(
  key: K,
  store: EntityStore<D, V>,
  cleanup: CleanupObject
)

 * Will create unique key index for entity store that will automatically add/update/delete items from the index on changes.
 */
export function createQueryFieldIndex<
  D,
  V,
  K extends keyof IndexableData<D & V>
>(
  key: K,
  store: EntityStore<D, V>,
  cleanup: CleanupObject
): QueryIndex<D, V, K> {
  type TargetEntity = Entity<D, V>;
  type TargetValue = IndexableData<TargetEntity>[K];
  type TargetValueInput = IndexValueInput<TargetValue>;

  /**
   * Index map. Example: topic has slug. Lets say we have 2 slugs 'foo' and 'bar'.
   *
   * This map would be like:
   * {
   *   foo: entity1,
   *   bar: entity2
   * }
   */
  const observableIndex = observable.map<
    TargetValue,
    IObservableArray<TargetEntity>
  >({});

  function getCurrentIndexValue(entity: TargetEntity): TargetValue {
    return entity[key] as TargetValue;
  }

  /**
   * Map keeping info to what index 'page' item currently belongs to
   */
  const currentItemIndexMap = new WeakMap<
    TargetEntity,
    IObservableArray<Entity<D, V>>
  >();

  try {
    set(window, `__index.${store.definition.config.name}.${key.toString()}`, {
      observableIndex,
    });
  } catch (error) {
    //
  }

  function updateItemIndexWithValue(
    entity: TargetEntity,
    indexValue: TargetValue
  ) {
    // Item might already be indexed somewhere
    const currentIndexList = currentItemIndexMap.get(entity);
    // Get where it should be indexed now
    const targetIndexList = observableMapGetOrCreate(
      observableIndex,
      indexValue,
      () => observable.array()