title: Send array in form data POST to PHP endpoint
body: <p>I'm sending values in http request to my PHP endpoint. I used to do like this:</p>
  
  <pre><code>let params = new URLSearchParams();
  params.append('postName', 'value');
  </code></pre>
  
  <p>but now I need to send array I tried multiple ways like this</p>
  
  <pre><code>params.append('postName', ["value1", "value2"]);
  </code></pre>
  
  <p>this convert to string value1,value2</p>
  
  <pre><code>params.append('postName', 'value1');
  params.append('postName', 'value2');
  </code></pre>
  
  <p>this just send two strings. How I can pass an array?</p>
  
  <p>I'm using this URLSearchParams because otherwise when I just send object or array then <code>$_POST['postName']</code> is not available in php endpoint.</p>