FieldArray TypeScript validate handler: Types of parameters 'values' and 'allValues' are incompatible.

[OnkelTem]

Are you submitting a bug report or a feature request?

bug report I think, but I'm not 100% sure

Unfortunately I cannot find any clue in the docs or on StackOverflow or here in the issues or among react-final-form-arrays issues.

What is the current behavior?

I cannot find out any way to declare a validate handler for a react-final-form-arrays's FieldArray field.

My validate handler is declared as:

  function validateNtpServerList(value: string, values: SystemDateTime) {
    return (value && value.length) || !values.ntp ? undefined : "The list cannot be empty";
  }

where SystemDateTime is the Form values type, declared as:

type SystemDateTime = {
  ntp: boolean
  datetime: Date
  ntpServers?: Array<string>
}

And in JSX I have a declaration like:

<FieldArray name="ntpServers" validate={ validateNtpServerList }>

which validate part triggers an TS error:

TS2322: Type '(value: string, values: SystemDateTime) => "The list cannot be empty" | undefined' is not assignable to type 'FieldValidator<string>'.
   Types of parameters 'values' and 'allValues' are incompatible.
     Type '{}' is missing the following properties from type 'SystemDateTime': ntp, datetime  

index.d.ts(97, 3): The expected type comes from property 'validate' which is declared here on type 'IntrinsicAttributes & FieldArrayProps<string, HTMLElement>'

The validator is declared in final-form/index.d.ts as:

type FieldValidator<FieldValue> = (
  value: FieldValue,
  allValues: object,
  meta?: FieldState<FieldValue>
) => any | Promise<any> 

where allValues is of type object which is indeed not compatible with my form values type which is SystemDateTime (see above).

I don't see any way to get it working.

What is the expected behavior?

Accept validate handler declaration. Or have this in the docs at least.

Sandbox Link

Here is an example:

https://codesandbox.io/s/react-final-form-arrays-validate-problem-qfgnd?file=/src/DateTimeForm.tsx
The problem is in the 39th line.

What's your environment?

"final-form": "^4.19.0",
"final-form-arrays": "^3.0.2",