Laravel Json Stringify responseText How to process it?

My Laravel code is given below

public function validateRegisterToBidForm(Request $request){

    $validationArray = $this->getValidationArray();

    $this->validate($request, $validationArray);
    return response()->json();

}//validateRegisterToBidForm

Output of above is received in Ajax If Error then I stringify the output Above and get following json

{"readyState":4,"responseText":"{\"fname\":[\"This field is missing or incorrect.\"],\"lname\":[\"This field is missing or incorrect.\"],\"email\":[\"This field is missing or incorrect\"],\"password\":[\"This field is missing or incorrect.\"],\"adr1\":[\"This field is missing or incorrect.\"],\"city\":[\"This field is missing or incorrect.\"],\"state\":[\"This field is missing or incorrect.\"],\"phone\":[\"This field is missing or incorrect.\"],\"primary_phone\":[\"This field is missing or incorrect.\"],\"pass_dri_license\":[\"This field is missing or incorrect.\"],\"card_type\":[\"This field is missing or incorrect.\"],\"cardno\":[\"This field is missing or incorrect\"],\"cvv\":[\"This field is missing or incorrect.\"],\"fname_b\":[\"This field is missing or incorrect.\"],\"lname_b\":[\"This field is missing or incorrect.\"],\"email_b\":[\"This field is missing or incorrect.\"],\"adr1_b\":[\"This field is missing or incorrect.\"],\"city_b\":[\"This field is missing or incorrect.\"],\"state_b\":[\"This field is missing or incorrect.\"],\"phone_b\":[\"This field is missing or incorrect.\"],\"primary_phone_b\":[\"This field is missing or incorrect.\"]}","status":422,"statusText":"Unprocessable Entity"}

How to extract values? What is the correct method?

via Codd