JSFiddle - React, Tailwind, and code Playground

HTML

<select name="empPositions[]" id="empPositions" style="width: 370px;" multiple="" data-placeholder="Choose a Position" required="">
    <option></option>
    <optgroup label="Admin">
        <option disabled="">There are no positions assigned to Admin</option>
    </optgroup>
    <optgroup label="Information Technology">
        <option value="1" selected="" disabled="">IT Developer</option>
        <option value="2">IT Geeks</option>
    </optgroup>
</select>

JavaScript

var opt = $('#empPositions option:selected').map(function(i,v) {
    return this.value;
}).get();
alert( opt );