Custom validations on multi select not getting Array

I’m trying to validate a “select multiple” input using a custom validation in the register callback like so

        <select
          name="multiSelect"
          multiple
          ref={register({
            validate: value => Array.isArray(value) && value.length > 1
          })}
        >
          <option value="opt1">Option 1</option>
          <option value="opt2">Option 2</option>
          <option value="opt3">Option 3</option>
          <option value="opt4">Option 4</option>
        </select>

However, the value passed to the validator function is always a String, the value of which is the topmost selected option.

Codesandbox available here https://codesandbox.io/embed/react-hook-form-1m47u

Is this a bug, or am I doing something wrong?

[bluebill1049]

Thanks releasing tonight 🤗

[bostrom]

Wow, that was fast! 💪

Thanks!