javascript reactjs react-hooks react-hook-form

How to change React-Hook-Form defaultValue with useEffect()?

I am creating a page for user to update personal data with React-Hook-Form. Once paged is loaded, I use useEffect to fetch the user's current personal data and set them into default value of the form.

I put the fetched value into defaultValue of <Controller />. However, it is just not showing in the text box. Here is my code:

import React, {useState, useEffect, useCallback} from 'react';
import { useForm, Controller } from 'react-hook-form'
import { URL } from '../constants';

const UpdateUserData = props => {
    const [userData, setUserData] = useState(null);
    const { handleSubmit, control} = useForm({mode: 'onBlur'});

    const fetchUserData = useCallback(async account => {
        const userData = await fetch(`${URL}/user/${account}`)
                            .then(res=> res.json());
        console.log(userData);
        setUserData(userData);
    }, []);

    useEffect(() => {
        const account = localStorage.getItem('account');
        fetchUserData(account);
    }, [fetchUserData])

    const onSubmit = async (data) => {
        // TODO
    }

    return (
        <div>
            <form onSubmit={handleSubmit(onSubmit)}>
                <div>
                    <label>User Name:</label>
                    <Controller
                        as={<input type='text' />}
                        control={control}
                        defaultValue={userData ? userData.name : ''}
                        name='name'
                    />
                </div>
                
                <div>
                    <label>Phone:</label>
                    <Controller
                        as={<input type='text' />}
                        control={control}
                        defaultValue={userData ? userData.phone : ''}
                        name='phone'
                    />
                </div>
                <button>Submit</button>
            </form>
        </div>
    );
}

export default UpdateUserData;

The called API is working well and the value is actually set to userData state.

{
  name: "John",
  phone: "02-98541566"
  ...
}

I also tried to setUserData with mock data in useEffect(), and it doesn't work either. Is there any problem in my above code?

Solution

You can use setValue (https://react-hook-form.com/api/useform/setvalue).

Import it from useForm:

const { handleSubmit, control, setValue} = useForm({ mode: 'onBlur' });

Then call it with the user data after it's received:

useEffect(() => {
    if (userData) {
        setValue([
            { name: userData.name }, 
            { phone: userData.phone }
        ]);
    }
}, [userData]);

You can remove the default values from the form.

EDIT: See alternative answers below if this does not work.