JSFiddle - React, Tailwind, and code Playground

HTML

<input type=checkbox name="check" value="NEW" checked>
<br>
<textarea id=textarea></textarea>

JavaScript

// my hide logic function
$.fn.hideTextareaOrNot = function() {
	if($(this).is(':checked') && $(this).val() == 'NEW') {
  	$('#textarea').hide();
  }
  else {
  	$('#textarea').show();
  }
}

// on change listener
$('input[name="check"]').change(function() {
	$(this).hideTextareaOrNot();
});

// on page load init
$('input[name="check"]').each(function(v) {
	$(this).hideTextareaOrNot();
});