Class QueryClient

packages/query-core/src/queryClient.ts:61–724

// CLASS

export class QueryClient {
  #queryCache: QueryCache
  #mutationCache: MutationCache
  #defaultOptions: DefaultOptions
  #queryDefaults: Map<string, QueryDefaults>
  #mutationDefaults: Map<string, MutationDefaults>
  #mountCount: number
  #unsubscribeFocus?: () => void
  #unsubscribeOnline?: () => void

  constructor(config: QueryClientConfig = {}) {
    this.#queryCache = config.queryCache || new QueryCache()
    this.#mutationCache = config.mutationCache || new MutationCache()
    this.#defaultOptions = config.defaultOptions || {}
    this.#queryDefaults = new Map()
    this.#mutationDefaults = new Map()
    this.#mountCount = 0
  }

  mount(): void {
    this.#mountCount++
    if (this.#mountCount !== 1) return

    this.#unsubscribeFocus = focusManager.subscribe(async (focused) => {
      if (focused) {
        await this.resumePausedMutations()
        this.#queryCache.onFocus()
      }
    })
    this.#unsubscribeOnline = onlineManager.subscribe(async (online) => {
      if (online) {
        await this.resumePausedMutations()
        this.#queryCache.onOnline()
      }
    })
  }

  unmount(): void {
    this.#mountCount--
    if (this.#mountCount !== 0) return

    this.#unsubscribeFocus?.()
    this.#unsubscribeFocus = undefined

    this.#unsubscribeOnline?.()
    this.#unsubscribeOnline = undefined
  }

  isFetching<TQueryFilters extends QueryFilters<any> = QueryFilters>(
    filters?: TQueryFilters,
  ): number {
    return this.#queryCache.findAll({ ...filters, fetchStatus: 'fetching' })
      .length
  }

  isMutating<
    TMutationFilters extends MutationFilters<any, any> = MutationFilters,
  >(filters?: TMutationFilters): number {