How to find out if there is a certain variable in the json response or not without js errors?

Question

JavaScript

In general, there is a script

$('form').submit(function(e){
        e.preventDefault();
        $form = $(this);
        $form.find('.notice').html('');
        $button = $form.find('button');
        $button.addClass('loading');
        $action = $form.attr('action');
        $.ajax({
          'url': $action,
          'type': "POST", 
          'dataType': "json", 
          'data': $form.serialize(), 
          'success': function(json) {
                                                  if(json.addons.redirect != null){
                                                   alert('yes');
                                                   }
            $button.removeClass('loading');
            $form.find('.notice').html('<div class='+json.response+'>'+json.msg+'</div>');
          }
        });
      });

The response generates the given php code

function ResponseCreate($response, $msg, $data){ 
    $datas = array(
      "response" => $response,
      "msg" => $msg,
      "addons" => $data,
    );
    
    $data_string = json_encode($datas);  
    exit($data_string);	
  }

And it turns out that the response may or may not be redirect , and how to check it without js errors, otherwise js stops when it does not see this variable

Answer 1

Wrap the redirect check in a try|catch and decide what to do in the catch block.
Just specify what format your json is in. Or rather, what type.