[Typescript] [Solid Query] typescript inference dependant on order of object keys

[vanillacode314]

Describe the bug

Typescript infers type of context as unknown if onMutate comes after onSuccess, onError or onSettled, in the following codeblock mutation1 typescript reports the type of context to be unknown which is wrong, in mutation2 typescript reports type of context to be { foo: string } | undefined which is expected and correct

const mutation1 = createMutation(() => ({
    onError: (error, variables, context) => console.log(context.foo),
    onMutate: ({}) => ({ foo: 'bar' }),
    onSuccess: (data, variables, context) => console.log(context.foo),
}));

const mutation2 = createMutation(() => ({
    onMutate: ({}) => ({ foo: 'bar' }),
    onError: (error, variables, context) => console.log(context.foo),
    onSuccess: (data, variables, context) => console.log(context.foo),
}));

Your minimal, reproducible example

https://stackblitz.com/edit/github-iy58hbhh?file=src%2Froutes%2Findex.tsx

Steps to reproduce

1. Go to the stackblitz url
2. Make sure node_modules is installed
3. Goto src/routes/index.tsx and hover over the context errors

Expected behavior

The order of keys don't matter and type of context is correctly inferred, I understand the workaround is pretty simple but I use a prettier plugin that orders all object keys alphabetically which is good for stable git diffs

How often does this bug happen?

Every time

Screenshots or Videos

No response

Platform

OS: Linux vc-arch 6.12.10-zen1-1-zen #1 ZEN SMP PREEMPT_DYNAMIC Sat, 18 Jan 2025 02:26:52 +0000 x86_64 GNU/Linux
Browser: N/A
Editor: Neovim

Tanstack Query adapter

solid-query

TanStack Query version

5.66.0

TypeScript version

5.7.3

Additional context

It only happens if the argument list of onMutate is non empty

[TkDodo]

please, for typescript related issues, typescript playground is so much better.

anyways, the issue is that the producer (onMutate) must come before the consumer (onError, onSuccess). This is a known TS limitation around intra expression inference:

• Intra expression inference doesn't work within reverse mapped types microsoft/TypeScript#53018

working playground