[docs] The variables is wrongly obtained in the "Mutation Filters" predicate example

[oleksandr-danylchenko]

Describe the bug

In the Mutation Filter docs section, there's a following example:

// Filter mutations using a predicate function
await queryClient.isMutating({
  predicate: (mutation) => mutation.options.variables?.id === 1,
})

Unfortunately, the mutation.options.variables expression would yield an error, because the variables doesn't exist on the options!

query/packages/query-core/src/types.ts

Lines 1038 to 1072 in 12d4542

	export interface MutationOptions<
	TData = unknown,
	TError = DefaultError,
	TVariables = void,
	TContext = unknown,
	> {
	mutationFn?: MutationFunction<TData, TVariables>
	mutationKey?: MutationKey
	onMutate?: (
	variables: TVariables,
	) => Promise<TContext | undefined> | TContext | undefined
	onSuccess?: (
	data: TData,
	variables: TVariables,
	context: TContext,
	) => Promise<unknown> | unknown
	onError?: (
	error: TError,
	variables: TVariables,
	context: TContext | undefined,
	) => Promise<unknown> | unknown
	onSettled?: (
	data: TData | undefined,
	error: TError | null,
	variables: TVariables,
	context: TContext | undefined,
	) => Promise<unknown> | unknown
	retry?: RetryValue<TError>
	retryDelay?: RetryDelayValue<TError>
	networkMode?: NetworkMode
	gcTime?: number
	_defaulted?: boolean
	meta?: MutationMeta
	scope?: MutationScope
	}

Instead, it exists on the state:

query/packages/query-core/src/mutation.ts

Lines 23 to 38 in 12d4542

	export interface MutationState<
	TData = unknown,
	TError = DefaultError,
	TVariables = unknown,
	TContext = unknown,
	> {
	context: TContext | undefined
	data: TData | undefined
	error: TError | null
	failureCount: number
	failureReason: TError | null
	isPaused: boolean
	status: MutationStatus
	variables: TVariables | undefined
	submittedAt: number
	}

Steps to reproduce

1. Go to https://tanstack.com/query/v5/docs/framework/react/guides/filters#mutation-filters
2. See the mentioned example for the predicate usage

Expected behavior

-predicate: (mutation) => mutation.options.variables?.id === 1,
+predicate: (mutation) => mutation.state.variables?.id === 1,

TanStack Query version

v5.64.1

TypeScript version

v5.7.3

[TkDodo]

thanks, would you like to make a PR to fix the docs?

[oleksandr-danylchenko]

Sure, here's the fix - #8589