JSFiddle - React, Tailwind, and code Playground

HTML

<form>
  First: <input data-default="First def" class="put-def" type="text"/>
  Second: <input data-default="Second def" class="put-def" type="text"/>
</form>
<button onClick="fill();">
Fill!
</button>

JavaScript

function fill(){
	$(".put-def").each(function(){
  	$(this).val($(this).data('default'));
  });
}