JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app ng-controller="MainCtrl">
    <ul>
        <li ng-repeat="(k,v) in events">Key {{k}} value {{v}}</li>
        <li ng-hide="Object.keys($scope.events).length>0">No events</li>
    </ul>
    <button ng-click="addEvent()">Add event to the existing {{Object.keys(events).length}}</button>
</div>

JavaScript

function MainCtrl($scope) {
    $scope.events = {1:'a', 2:'b'};

    $scope.addEvent = function() {
        $scope.events[3]='c';
    };
}