JSFiddle - React, Tailwind, and code Playground

HTML

<input name="firstName" id="firstName" type="text" class="known-questions">
<input name="lastName" id="lastName" type="text" class="known-questions">
<input name="email" id="email" type="email" class="known-questions">
<input name="45435345345" id="45435345345" type="text" class="unknown-questions">
<input name="43443539864" id="43443539864" type="text" class="unknown-questions">
<input name="43344243529" id="43344243529" type="text" class="unknown-questions">
<h3>
results
</h3>
<textarea style="width:100%; height:500px"></textarea>

JavaScript

// add some values for demo
$('input').val(function(i){
   return 'Item #'+(i+1)
});


var data ={}
$('.known-questions').each(function(){
    data[this.name] = this.value;
});

data.responses = $('.unknown-questions').map(function(){
   return {questionKey: this.id, responseText:this.value}
}).get();

$('textarea').val(JSON.stringify(data,null,4))