JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" name="question[]" placeholder="multipleChoice"><br><br>
<input type="text" name="question[]" placeholder="trueFalse"><br><br>
<input type="text" name="question[]" placeholder="shortAnswer"><br><br>
<input type="text" name="question[]" placeholder="shortAnswer"><br><br>
<input type="text" name="question[]" placeholder="description"><br><br>
<input type="text" name="question[]" placeholder="multipleChoice"><br><br>
<input type="text" name="question[]" placeholder="multipleChoice"><br><br>
<input type="text" name="question[]" placeholder="trueFalse"><br><br>

<span id="result"></span>

JavaScript

$(document).ready(function(){
  var try1;
  var arrayLen = $('input[name="question[]"]').length;
  var numArray = [];
  var convertedArray = [];
  for(i = 1; i <= arrayLen; i++){
  	numArray.push(i);
  }

  $('input[name="question[]"').keydown(function(e){
		var val = $(this).val();
  	if(e.which === 8 || e.keyCode === 8){
    	numArray.push(parseInt($(this).attr('newval')));
      $(this).removeAttr('newval');
    } else {
    	val += e.key;
      if(numArray.indexOf(parseInt(val)) != -1){
        $('#result').html("available");
        $(this).attr('newval', e.key);
        numArray.splice(numArray.indexOf(parseInt(val)), 1);
      } else{
        $("#result").html("not available");
        e.preventDefault();
      }
    }
  });
  
});