JSFiddle - React, Tailwind, and code Playground

HTML

<body ng-app="App" ng-controller="Main">
    <select ng-model='selection'
            ng-options='t as t.label group by t.group for t in things | orderBy:"label"'>
    </select>
    <pre>{{selection | json}}</pre>
</body>

JavaScript

var App = angular.module('App', []);

App.controller("Main", function($scope) {
    $scope.things = [
        {group: 'GroupB', label: 'FF'},
        {group: 'GroupA', label: 'EE'},
        {group: 'GroupB', label: 'DD'},
        {group: 'GroupA', label: 'CC'},
        {group: 'GroupB', label: 'BB'},
        {group: 'GroupA', label: 'AA'}
    ];
});