Method has

packages/db/src/collection/state.ts:370–384

* Check if a key exists in the collection (virtual derived state)

(key: TKey)

   * Check if a key exists in the collection (virtual derived state)
   */
  public has(key: TKey): boolean {
    const { optimisticDeletes, optimisticUpserts, syncedData } = this
    // Check if optimistically deleted
    if (optimisticDeletes.has(key)) {
      return false
    }

    // Check optimistic upserts first
    if (optimisticUpserts.has(key)) {
      return true
    }

    // Fall back to synced data
    return syncedData.has(key)
  }

  /**
   * Get all keys (virtual derived state)