JSFiddle - React, Tailwind, and code Playground

HTML

<select name="countries" id="countries" MULTIPLE size="8">
    <option value="all">Select all</option>
   <option value="UK">UK</option>
   <option value="US">US</option>
   <option value="Canada">Canada</option>
   <option value="France">France</option>
   <option value="India">India</option>
   <option value="China">China</option>
</select>

JavaScript

$('#countries').change(function() {
        if($(this).val() == 'all')
        {
            $('#countries option').prop('selected', true);
        }
    });