Exported formOptions with listeners fails declaration emit: FormListenersPropsField cannot be named

[jzxhuang]

Describe the bug

When exporting an inferred formOptions(...) value that includes listeners, TypeScript fails during declaration emit with TS4023.

The inferred exported type references TanStack Form's internal FormListenersPropsField type from @tanstack/form-core/dist/esm/FormApi. Since that type is not publicly exported/nameable, TypeScript cannot serialize the exported formOptions(...) value into a .d.ts file.

This can happen even without explicitly setting declaration: true. For example, composite: true is enough to reproduce because composite TypeScript projects emit declarations by default.

Minimal failing code:

import { formOptions } from '@tanstack/react-form'

export const reproFormOptions = formOptions({
  defaultValues: {
    country: '',
    province: '',
  },
  listeners: {
    onChange: ({ formApi }) => {
      formApi.setFieldValue('province', '')
    },
  },
})

The error is:

src/form-options.ts(12,14): error TS4023: Exported variable 'reproFormOptions' has or is using name 'FormListenersPropsField' from external module ".../node_modules/.pnpm/@tanstack+form-core@1.33.0/node_modules/@tanstack/form-core/dist/esm/FormApi" but cannot be named.

Your minimal, reproducible example

https://codesandbox.io/p/github/jzxhuang/tanstack-form-form-options-type-bug/main?import=true

Steps to reproduce

See codesandbox, snippet above, or https://github.com/jzxhuang/tanstack-form-form-options-type-bug

Expected behavior

TypeScript should be able to emit declarations for an exported formOptions(...) value that uses form listeners.

In particular, the inferred public type of formOptions(...) should not require consumers' declaration emit to name an internal, non-exported TanStack Form type.

How often does this bug happen?

None

Screenshots or Videos

No response

Platform

Reproduces with TypeScript 6.0.3.

Also verified with TypeScript 5.8.3 using:

pnpm --package typescript@5.8.3 dlx tsc -p tsconfig.app.json --pretty false --noEmitOnError

TanStack Form adapter

None

TanStack Form version

1.33.0

TypeScript version

6.0.3

Additional context

No response