upstream-tanstack-query/docs/framework/lit/reference/functions/useIsMutating.md

id, title

id	title
useIsMutating	useIsMutating

function useIsMutating(
   host,
   filters,
   queryClient?): IsMutatingAccessor;

Defined in: packages/lit-query/src/useIsMutating.ts:147

Creates a Lit reactive controller that tracks how many matching mutations are currently pending.

When filters is a function, it is re-read during host updates so the count can follow reactive host state. If queryClient is omitted, the controller resolves the client from the nearest connected QueryClientProvider.

Parameters

host

ReactiveControllerHost

The Lit reactive controller host that owns the cache subscription.

filters

Accessor<MutationFilters<unknown, Error, unknown, unknown>> = {}

Mutation filters, or a getter that returns mutation filters.

queryClient?

QueryClient

Optional explicit query client. Provide this for controllers that should not resolve a client from Lit context.

Returns

IsMutatingAccessor

An accessor for the current number of matching pending mutations.

Example

import { LitElement, html } from 'lit'
import { useIsMutating } from '@tanstack/lit-query'

class MutationStatus extends LitElement {
  private readonly savesPending = useIsMutating(this, {
    mutationKey: ['save-project'],
  })

  render() {
    return html`<span>${this.savesPending()} saves pending</span>`
  }
}