Method reducer

packages/query-core/src/query.ts:628–696

(
      state: QueryState<TData, TError>,
    )

  #dispatch(action: Action<TData, TError>): void {
    const reducer = (
      state: QueryState<TData, TError>,
    ): QueryState<TData, TError> => {
      switch (action.type) {
        case 'failed':
          return {
            ...state,
            fetchFailureCount: action.failureCount,
            fetchFailureReason: action.error,
          }
        case 'pause':
          return {
            ...state,
            fetchStatus: 'paused',
          }
        case 'continue':
          return {
            ...state,
            fetchStatus: 'fetching',
          }
        case 'fetch':
          return {
            ...state,
            ...fetchState(state.data, this.options),
            fetchMeta: action.meta ?? null,
          }
        case 'success':
          const newState = {
            ...state,
            ...successState(action.data, action.dataUpdatedAt),
            dataUpdateCount: state.dataUpdateCount + 1,
            ...(!action.manual && {
              fetchStatus: 'idle' as const,
              fetchFailureCount: 0,
              fetchFailureReason: null,
            }),
          }
          // If fetching ends successfully, we don't need revertState as a fallback anymore.
          // For manual updates, capture the state to revert to it in case of a cancellation.
          this.#revertState = action.manual ? newState : undefined

          return newState
        case 'error':
          const error = action.error
          return {
            ...state,
            error,
            errorUpdateCount: state.errorUpdateCount + 1,
            errorUpdatedAt: Date.now(),
            fetchFailureCount: state.fetchFailureCount + 1,
            fetchFailureReason: error,
            fetchStatus: 'idle',
            status: 'error',
            // flag existing data as invalidated if we get a background error
            // note that "no data" always means stale so we can set unconditionally here
            isInvalidated: true,
          }
        case 'invalidate':