import React from 'react'; import { Controller, useFieldArray, useFormState, useForm, Control, } from 'react-hook-form'; type FormValues = { test: { firstName: string; lastName: string; keyValue: { name: string }[]; }[]; }; function NestedArray({ control, index, }: { control: Control; index: number; }) { const { fields, append, prepend, swap, move, remove, insert, update } = useFieldArray({ name: `test.${index}.keyValue` as 'test.0.keyValue', control, }); const { touchedFields, dirtyFields } = useFormState({ control, }); const renderCountRef = React.useRef(0); renderCountRef.current++; return (
    {fields.map((item, i) => ( } name={`test.${index}.keyValue.${i}.name`} control={control} /> ))}
{JSON.stringify(dirtyFields)}
{JSON.stringify(touchedFields)}
{renderCountRef.current}
); } export default () => { const { register, control, reset, setValue, handleSubmit } = useForm({ defaultValues: { test: [ { firstName: 'Bill', lastName: 'Luo', keyValue: [{ name: '1a' }, { name: '1c' }], }, ], }, }); const { fields, append, prepend, swap, move, insert, remove, update } = useFieldArray({ control, name: 'test', }); const renderCountRef = React.useRef(0); const [result, setResult] = React.useState({}); renderCountRef.current++; return (
setResult(e))}> {fields.map((item, index) => { return (
); })}
{renderCountRef.current}

{JSON.stringify(result)}

); };