Class QueryCache

packages/query-core/src/queryCache.ts:123–353

 * ```
 */
export class QueryCache extends Subscribable<QueryCacheListener> {
  #queries: QueryStore

  constructor(public config: QueryCacheConfig = {}) {
    super()
    this.#queries = new Map<string, Query>()
  }

  /**
   * Returns the existing `Query` instance for the given options' `queryKey`/`queryHash`, or
   * builds and adds a new one to the cache if none exists yet. Used by framework adapters and
   * plugins (e.g. broadcast/persistence) that need to get-or-create a `Query` directly, bypassing
   * the reactive `QueryObserver` machinery.
   *
   * @example
   * ```ts
   * const queryCache = queryClient.getQueryCache()
   *
   * const query = queryCache.build(queryClient, {
   *   queryKey: ['posts'],
   *   queryFn: fetchPosts,
   * })
   * ```
   */
  build<
    TQueryFnData = unknown,
    TError = DefaultError,
    TData = TQueryFnData,
    TQueryKey extends QueryKey = QueryKey,
  >(
    client: QueryClient,
    options: WithRequired<
      QueryOptions<TQueryFnData, TError, TData, TQueryKey>,
      'queryKey'
    >,
    state?: QueryState<TData, TError>,
  ): Query<TQueryFnData, TError, TData, TQueryKey> {
    const queryKey = options.queryKey
    const queryHash =
      options.queryHash ?? hashQueryKeyByOptions(queryKey, options)
    let query = this.get<TQueryFnData, TError, TData, TQueryKey>(queryHash)

    if (!query) {
      query = new Query({
        client,
        queryKey,
        queryHash,
        options: client.defaultQueryOptions(options),
        state,
        defaultOptions: client.getQueryDefaults(queryKey),
      })
      this.add(query)
    }

    return query
  }

  /** @internal */