React hook form: How to can I use onChange on React Hook Form Version 7.0

Question

Previously I used to write like this:

<input className="form-control" name="productImage" type='file' onChange={handleImageUpload} ref={register({ required: true })} />

After the update I have to write like this:

<input className="form-control" type="file" {...register('productImage', { required: true })} />

How do I use onChange={handleImageUpload} on the updated version of React Hook Form? Here is the migration docs

Please pardon my mistakes in the manner of asking the question. I'm new to these things. Thank you.

Answer 1

You just have to move the onChange props after {...register(...)}

const productImageField = register("productImage", { required: true });

return (
    <input
        className="form-control"
        type="file"
        {...productImageField}
        onChange={(e) => {
          productImageField.onChange(e);
          handleImageUpload(e);
     }}
    />
)

(Dec 3 2021) edit: this approach is no longer correct since react-hook-form v7.16.0's changes, see @Bill's answer.

Answer 2

https://github.com/react-hook-form/react-hook-form/releases/tag/v7.16.0

V7.16.0 has introduced this new API for custom onChange.

<input
  type="text"
  {...register('test', {
    onChange: (e) => {},
    onBlur: (e) => {},
  })}
/>

Answer 3

In register documentation https://react-hook-form.com/api/useform/register, sample exists on Custom onChange, onBlur section :

// onChange got overwrite by register method
<input onChange={handleChange} {...register('test')} />

// register's onChange got overwrite by register method
<input {...register('test')} onChange={handleChange}/>

const firstName = register('firstName', { required: true })
<input 
  onChange={(e) => {
    firstName.onChange(e); // method from hook form register
    handleChange(e); // your method
  }}
  onBlur={firstName.onBlur}
  ref={firstName.ref} 
/>

So for your case :

const productImageRegister = register("productImage", {required: true})
<input className="form-control"
       type="file"
       {...productImageRegister }
       onChange={e => {
           productImageRegister.onChange(e);
           handleImageUpload(e);
       }} />

Answer 4

For me, decoration solution worked

const fieldRegister = register("productImage", {required: true})
const origOnChange = fieldRegister.onChange
fieldRegister.onChange = (e) => {
    const res = origOnChange(e)
    const value = e.target.value
    // do something with value
    return res
}

For field declaration use

<input {...fieldRegister}/>

Answer 5

Was stuck with the same problem. For me the problem was that my onChange was above the react-hook-form's {...register} and moving it below the register solved the problem for me!!

Answer 6

I faced a similar issue recently when migrating to V7. If it can help anybody.

A parent component handling the form was passing down to a wrapper the register function, the wrapper passing it down again to an input that needed debouncing on change.

I called the register formLibraryRef in case I wanted to use a different library later but overall I had to do something like:

const { onChange, ...rest } = formLibraryRef(inputName);

pass the onChange to the function that is itself passed to the native onChange event of the input:

const handleDebouncedChange: (event: React.ChangeEvent<HTMLInputElement>) => void = (
    event: ChangeEvent<HTMLInputElement>,
  ) => {
    onChange(event);
    if (preCallback) {
      preCallback();
    }
    debounceInput(event);
  };

and then pass the rest to the input:

<input
  aria-label={inputName}
  name={inputName}
  data-testid={dataTestId}
  className={`form-control ...${classNames}`}
  id={inputId}
  onChange={handleDebouncedChange}
  onFocus={onFocus}
  placeholder={I18n.t(placeholder)}
  {...rest}
/>

The register section in the docs here: https://react-hook-form.com/migrate-v6-to-v7/ gives a bit more info on how to get the onChange and shows an example for Missing ref.