Alternative to "skipToken"

[donaldpipowitch]

I'm following query.gg and the docs and I'm a bit confused regarding skipToken. It is the suggested solution to make disabling of queries type safe, but there is also a warning that refetch will no longer work correctly.

Are there ay reasons to not do this instead?:

import * as React from 'react';
import { useQuery } from '@tanstack/react-query';

function useAuction(productId: string | undefined, otherId: string | undefined) {
  const enabled = productId && otherId;
  return useQuery({
    queryKey: ['auction', productId, otherId],
    enabled: Boolean(enabled),
    queryFn: () => {
      if (!enabled) throw new Error('Not enabled.');
      return fetchAuction(productId, otherId);
    },
  });
}

function fetchAuction(productId: string, otherId: string) {}

Similar to skipToken there is another check (!enabled), but instead of returning skipToken an error is thrown. This also makes it type safe to use productId and otherId and refetch should still works as intended or?

Follow up question: is throw new Error('Not enabled.'); safe? Or does it need to be return Promise.reject(new Error('Not enabled.'));.

[TkDodo]

Are there ay reasons to not do this instead?

You can do that, but closing over enabled means it should technically go into the queryKey, at least that’s what the lint rules will tell you. But this will also throw if you call refetch() while enabled is false, same as skipToken, so it doesn’t achieve anything really.

** is throw new Error('Not enabled.'); safe? Or does it need to be return Promise.reject(new Error('Not enabled.'));.**

throwing is safe, we’ll transform that to a failed promise internally.

---

the use-case that enabled covers that skipToken does not is a permanently disabled query:

useQuery({
  queryKey,
  queyFn,
  enabled: false
})

so that you then can call refetch() to trigger “on demand” querying. This will not work with queryFn: skipToken because there is no queryFn to execute.

However, this pattern (a permanently disabled observer) is discouraged. There are usually better ways to achieve what you want, like Lazy Queries.

[donaldpipowitch]

Thank you for the quick answer!