How to validate data before calling onSubmit in React Hook Form?

I would simply like to validate the data on onChange. Here I have tried using rules prop from Controller but It validate data onSubmit. How can I call my position method every time there’s a change in this combobox field?

<Controller
  control={control}
  name={`${id}_${item.item_id}`}
  rules={{
    validate: {
      positive: (data) => {
        console.log(data);
        return false;
      },
    },
  }}
  render={({ field }) => {
    return (
      <EuiComboBox
        options={itemsOptions}
        placeholder="Select Item"
        isClearable={true}
        singleSelection={true}
        selectedOptions={field.value}
        onChange={field.onChange}
      />
    );
  }}
/>;