issue: Type issues with string array when using useFieldArray hook

[milindgoel15]

Version Number

^7.50.1

Codesandbox/Expo snack

https://codesandbox.io/p/sandbox/react-hook-form-usefieldarray-forked-2vtmkp?file=%2Fsrc%2Findex.tsx%3A10%2C45

Steps to reproduce

1. Add default values in string array format
2. Notice it will throw type error

Type 'string' is not assignable to type 'never'.typescript(2322)
fieldArray.d.ts(6, 5): The expected type comes from property 'name' which is declared here on type 'UseFieldArrayProps<{ test: string[]; }, never, "id">'

Expected behaviour

No type error. It should work normally with string based array as it does it custom object based array.

What browsers are you seeing the problem on?

none, type error thrown in IDE

Relevant log output

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[milindgoel15]

More details as the issue template didnt had any description field:

Just to note that on my code, it also throws type error on append() function

Argument of type 'string' is not assignable to parameter of type '{ name: string; } | Details | ({ name: string; } | Details)[]'

Moreover, I have also made a feature.tsx file with my code to reproduce the issue with my code. Although my code works normally except the type error. If required, I can setup a minimal reproducible repo with my code.

[Moshyfawn]

Your codesandbox is inaccessible.

[milindgoel15]

Didnt notice it was private. Changed visibility to public. Please lemme know what other details to provide.

[Moshyfawn]

From the useFieldArray docs:

Does not support flat field array.

useFieldArray has to work with objects as opposed to simple types like string, because RHF has to keep track of each field by inserting an id property.

So the solution would be to convert test: ["Bill", "John"] to test: [{ name: "Bill" }, { name: "John" }].

[milindgoel15]

But it appears to work even with simple type.

Edit: Although I can surely modify my useForm schema and map over the data array to extract the value in a separate array when saving to DB.