Method createResult

src/queryCore/core/queryObserver.ts:459–626

(
    query: Query<TQueryFnData, TError, TQueryData, TQueryKey>,
    options: QueryObserverOptions<
      TQueryFnData,
      TError,
      TData,
      TQueryData,
      TQueryKey
    >
  )

  }

  protected createResult(
    query: Query<TQueryFnData, TError, TQueryData, TQueryKey>,
    options: QueryObserverOptions<
      TQueryFnData,
      TError,
      TData,
      TQueryData,
      TQueryKey
    >
  ): QueryObserverResult<TData, TError> {
    const prevQuery = this.currentQuery
    const prevOptions = this.options
    const prevResult = this.currentResult
    const prevResultState = this.currentResultState
    const prevResultOptions = this.currentResultOptions
    const queryChange = query !== prevQuery
    const queryInitialState = queryChange
      ? query.state
      : this.currentQueryInitialState
    const prevQueryResult = queryChange
      ? this.currentResult
      : this.previousQueryResult

    const { state } = query
    let { dataUpdatedAt, error, errorUpdatedAt, isFetching, status } = state
    let isPreviousData = false
    let isPlaceholderData = false
    let data: TData | undefined

    // Optimistically set result in fetching state if needed
    // @ts-ignore
    if (options.optimisticResults) {
      const mounted = this.hasListeners()

      const fetchOnMount = !mounted && shouldFetchOnMount(query, options)

      const fetchOptionally =
        mounted && shouldFetchOptionally(query, prevQuery, options, prevOptions)

      if (fetchOnMount || fetchOptionally) {
        isFetching = true
        if (!dataUpdatedAt) {
          status = 'loading'
        }
      }
    }

    // Keep previous data if needed
    if (
      options.keepPreviousData &&
      !state.dataUpdateCount &&
      prevQueryResult?.isSuccess &&
      status !== 'error'
    ) {
      data = prevQueryResult.data
      dataUpdatedAt = prevQueryResult.dataUpdatedAt
      status = prevQueryResult.status
      isPreviousData = true