useIsMutating

import { useIsMutating } from '@effector-tanstack-query/react'

function SaveIndicator() {
  const mutating = useIsMutating()
  return mutating > 0 ? <span>Saving…</span> : null
}

Returns the number of mutations currently running in the scope’s QueryClient. Mirrors useIsFetching for mutations, and matches useIsMutating from @tanstack/react-query.

Filtering

Pass a MutationFilters object to count only matching mutations. Filters match by value, so a fresh object literal each render is fine.

// Only mutations registered with mutationKey ['createUser']
const creating = useIsMutating({ mutationKey: ['createUser'] })

MutationFilters is re-exported for convenience:

import type { MutationFilters } from '@effector-tanstack-query/react'

Scope awareness

The client is resolved via useUnit($queryClient), so each fork scope counts its own running mutations and re-subscribes when the scope’s $queryClient changes. With no client set, the hook returns 0 rather than throwing.

Type signature

function useIsMutating(filters?: MutationFilters): number

The return is always a plain number, never number | undefined.