How can I get optgroup label when select an option in vuejs? - vuejs2

Question

I want to get country group name when select option. I've countries with several group like
<template>
<select id="countries" v-model="country" #change="getCountryGroup($event)">
<optgroup label="Asia">
<option value="AF">Afghanistan</option>
<option value="AM">Armenia</option>
<option value="AZ">Azerbaijan</option>
...
<option value="BD">Bangaldesh</option>
...
</optgroup>
<optgroup label="Australia / Oceania">
<option value="AS">American Samoa</option>
<option value="AU">Australia</option>
<option value="CK">Cook Islands</option>
</optgroup>
<optgroup label="Africa">
<option value="DZ">Algeria</option>
<option value="AM">Angola</option>
<option value="AZ">Azerbaijan</option>
</optgroup>
<optgroup label="South America">
<option value="AR">Argentina</option>
<option value="BO">Bolivia</option>
<option value="BR">Brazil</option>
</optgroup>
<optgroup label="North America">
<option value="US">United States</option>
<option value="UM">United States Minor Outlying Islands</option>
<option value="CA">Canada</option>
</optgroup>
<optgroup label="Europe">
<option value="UK">United Kingdom</option>
<option value="AL">Albania</option>
<option value="AD">Andorra</option>
</optgroup>
</select>
</template>
Suppose when I select Bangladesh then I want to get optgroup name Asia. Here is my vueJs method
getCountryGroup: function(event){
console.log( event.target.getAttribute('label') );
}

Answer 1

Here are two steps
Get the selected index
Find the selected option
Select the parent element (optgroup) for the selected option
Finally, get the label (Country group)
getCountryGroup: function(event){
// 1. Get the selected index
const index = event.target.selectedIndex;
// 2. Find the selected option
const option = event.target.options[index];
// 3. Select the parent element (optgroup) for the selected option
const optgroup = option.parentElement;
// 4. Finally, get the label (Country group)
const countryGroup = optgroup.getAttribute('label');
console.log(countryGroup);
}
Here is the demo https://codepen.io/maab16/pen/KKKpJba