transactional list cache

transactionalCache.ts

interface WithId {
  id: string | number;
}

type Transaction<T extends WithId = WithId> = T[];

export class TransactionalCache<T extends WithId = WithId> {
  private remove: T[];
  private update: T[];
  private add: T[];

  updateTransactions = (transactions: Transaction<T>, callback: Function) => {
    this.removeItems(transactions);
    this.addItems(transactions);
    this.updateItems(transactions);

    callback();
  };

  flush = () => {
    this.remove = [];
    this.add = [];
    this.update = [];
  };

  getTransactions = () => ({add, update, remove});

  private removeItems = (toRemove: T[]) => {
    const toIds = toRemove.map(({ id }) => id);
    this.remove = [...this.remove.filter(({ id }) => {
      return toIds.indexOf(id) === -1;
    }), ...toRemove];

    this.add = [...this.add.filter(({ id }) => {
      return toRemove.indexOf(id) === -1;
    });

    this.update = this.update.filter(({ id }) => {
      return toRemove.indexOf(id) === -1;
    });
  };

  private addItems = (toAdd: T[]) => {
    const toAddIds = toAdd.map(({ id }) => id);
    this.add = [...this.add.filter(({ id }) => {
      return toAddIds.indexOf(id) === -1;
    }), ...toAdd];
  };


  private updateItems = (toUpdate: T[]) => {
    const toIds = toUpdate.map(({ id }) => id);
    this.update = [...this.update.filter(({ id }) => {
      return toIds.indexOf(id) === -1;
    }), ...toUpdate];
  };
}