Suggestion: improve ergonomics of *InfiniteOptions types

[OliverJAsh]

Describe the bug

The docs suggest using infiniteQueryOptions to abstract infinite query options. For example:

import { infiniteQueryOptions } from '@tanstack/react-query';

export const queryOptions = infiniteQueryOptions({
  queryKey: ['foo'],
  queryFn: ({ pageParam }) => Promise.resolve({ foo: 'bar' }),
  initialPageParam: 1,
  getNextPageParam: (lastPage, allPages, lastPageParam) => lastPageParam + 1,
});

However, when using TypeScript's isolated declarations (isolatedDeclarations), all module exports must have type annotations. For this reason it would be preferable to use a type annotation rather than the infiniteQueryOptions type constructor.

The problem with this, however, is it's very verbose:

import type {
  DefaultError,
  InfiniteData,
  QueryKey,
  UnusedSkipTokenInfiniteOptions,
} from '@tanstack/react-query';

type MyResponse = {
  foo: string;
};

export const queryOptions: UnusedSkipTokenInfiniteOptions<
  MyResponse,
  DefaultError,
  InfiniteData<MyResponse, number>,
  QueryKey,
  number
> = {
  queryKey: ['foo'],
  queryFn: ({ pageParam }) => Promise.resolve({ foo: 'bar' }),
  initialPageParam: 1,
  getNextPageParam: (lastPage, allPages, lastPageParam) => lastPageParam + 1,
};

Except for the first and last type parameters provided to UnusedSkipTokenInfiniteOptions, all the others could theoretically just use the defaults. However, we're forced to provide them because we need to provide TPageParam (the last type parameter), otherwise it would default to unknown.

Given more TypeScript users will likely be looking to enable isolated declarations in the future and thus be required to add type annotations, I wonder if we could make these types more ergonomic.

One idea would be to move the position of the TPageParam type parameter in the *InfiniteOptions types, so we can benefit from defaults. For example, if it was moved from last to second position then the example above would look much better:

import type {
  DefaultError,
  InfiniteData,
  QueryKey,
  UnusedSkipTokenInfiniteOptions,
} from '@tanstack/react-query';

type MyResponse = {
  foo: string;
};

export const queryOptions: UnusedSkipTokenInfiniteOptions<
  MyResponse,
  number
> = {
  queryKey: ['foo'],
  queryFn: ({ pageParam }) => Promise.resolve({ foo: 'bar' }),
  initialPageParam: 1,
  getNextPageParam: (lastPage, allPages, lastPageParam) => lastPageParam + 1,
};

-type UnusedSkipTokenInfiniteOptions<TQueryFnData, TError = DefaultError, TData = InfiniteData<TQueryFnData>, TQueryKey extends QueryKey = QueryKey, TPageParam = unknown> = OmitKeyof<UseInfiniteQueryOptions<TQueryFnData, TError, TData, TQueryFnData, TQueryKey, TPageParam>, 'queryFn'> & {
    queryFn?: Exclude<UseInfiniteQueryOptions<TQueryFnData, TError, TData, TQueryFnData, TQueryKey, TPageParam>['queryFn'], SkipToken | undefined>;
};
+type UnusedSkipTokenInfiniteOptions<TQueryFnData, TPageParam = unknown, TError = DefaultError, TData = InfiniteData<TQueryFnData, TPageParam>, TQueryKey extends QueryKey = QueryKey> = OmitKeyof<UseInfiniteQueryOptions<TQueryFnData, TError, TData, TQueryFnData, TQueryKey, TPageParam>, 'queryFn'> & {
    queryFn?: Exclude<UseInfiniteQueryOptions<TQueryFnData, TError, TData, TQueryFnData, TQueryKey, TPageParam>['queryFn'], SkipToken | undefined>;
};

Your minimal, reproducible example

N/A

Steps to reproduce

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Expected behavior

N/A

How often does this bug happen?

None

Screenshots or Videos

No response

Platform

N/A

Tanstack Query adapter

None

TanStack Query version

N/A

TypeScript version

No response

Additional context

No response

[TkDodo]

using the defaults doesn’t really help much because using them will make features where type inference is necessary, like select, not work.

We use isolatedModules without explicitly giving everything a return type annotation, so I’m not really sure why inference can’t be used. We also can’t change the type param order because that would be a breaking change.

Moving to a discussion.

[OliverJAsh]

Sorry, I was talking about isolatedDeclarations, not isolatedModules. Hopefully that clarifies things?

[samhh]

Such inference is incompatible with isolated declarations: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-5.html#isolated-declarations

There is already some early-stage tooling such as oxc-transform that leverages this feature, dramatically speeding up typechecking in large projects by essentially eliminating the time taken to perform declaration emit.

This is still quite immature in the ecosystem but it's the direction of travel.