Remove duplicate id in select box using Jquery

============== Input ==============
<select>
<option value="1">val-1<option>
<option value="2">val-5<option>
<option value="1">val-7<option>
<option value="3">val-8<option>
</select>
============== Input ==============

var map = {};
			$('select option').each(function () {
			    if (map[this.value]) {
			        $(this).remove()
			    }
			    map[this.value] = true;
			})
      
============== Output ==============
<select>
<option value="1">val-1<option>
<option value="2">val-5<option>
<option value="3">val-8<option>
</select>
============== Output ==============