클라이언트-서버 통신을 위해 HTML5 FormData를 JSON으로 변환하는 방법은 무엇입니까?

<code class="javascript">var object = {};
formData.forEach(function(value, key){
    object[key] = value;
});
var json = JSON.stringify(object);</code>

<code class="javascript">var object = {};
formData.forEach((value, key) => object[key] = value);
var json = JSON.stringify(object);</code>

<code class="javascript">var object = {};
formData.forEach((value, key) => {
    if(!Reflect.has(object, key)){
        object[key] = value;
        return;
    }
    if(!Array.isArray(object[key])){
        object[key] = [object[key]];    
    }
    object[key].push(value);
});
var json = JSON.stringify(object);</code>

<code class="javascript">var request = new XMLHttpRequest();
request.open('POST', 'http://example.com/submitform.php');
request.send(formData);</code>

<code class="javascript">fetch('http://example.com/submitform.php', {
  method: 'POST',
  body: formData
}).then((response) => { 
  // do something with response here... 
});</code>