Method fetch

packages/query-core/src/query.ts:590–820

* Fetches the query, i.e. runs its `queryFn` (through any configured * retryer/behavior) and updates the query's state with the result. * - If a fetch is already in flight, returns its promise instead of * starting a new one, unless `fetchOptions.cancelRefetch` is set and the * query

(
    options?: QueryOptions<TQueryFnData, TError, TData, TQueryKey>,
    fetchOptions?: FetchOptions<TQueryFnData>,
  )

   *   before fetching.
   */
  async fetch(
    options?: QueryOptions<TQueryFnData, TError, TData, TQueryKey>,
    fetchOptions?: FetchOptions<TQueryFnData>,
  ): Promise<TData> {
    if (
      this.state.fetchStatus !== 'idle' &&
      // If the promise in the retryer is already rejected, we have to definitely
      // re-start the fetch; there is a chance that the query is still in a
      // pending state when that happens
      this.#retryer?.status() !== 'rejected'
    ) {
      if (this.state.data !== undefined && fetchOptions?.cancelRefetch) {
        // Silently cancel current fetch if the user wants to cancel refetch
        this.cancel({ silent: true })
      } else if (this.#retryer) {
        // make sure that retries that were potentially cancelled due to unmounts can continue
        this.#retryer.continueRetry()
        // Return current promise if we are already fetching
        return this.#retryer.promise
      }
    }

    // Update config if passed, otherwise the config from the last execution is used
    if (options) {
      this.setOptions(options)
    }

    // Use the options from the first observer with a query function if no function is found.
    // This can happen when the query is hydrated or created with setQueryData.
    if (!this.options.queryFn) {
      const observer = this.observers.find((x) => x.options.queryFn)
      if (observer) {
        this.setOptions(observer.options)
      }
    }

    if (process.env.NODE_ENV !== 'production') {
      if (!Array.isArray(this.options.queryKey)) {
        console.error(
          `As of v4, queryKey needs to be an Array. If you are using a string like 'repoData', please change it to an Array, e.g. ['repoData']`,
        )
      }
    }

    const abortController = new AbortController()

    // Adds an enumerable signal property to the object that
    // which sets abortSignalConsumed to true when the signal
    // is read.
    const addSignalProperty = (object: unknown) => {
      Object.defineProperty(object, 'signal', {
        enumerable: true,
        get: () => {
          this.#abortSignalConsumed = true
          return abortController.signal
        },
      })
    }