JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>

<html lang="en" ng-app="app">
  <head>
    <meta charset="utf-8" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.1/angular.min.js"></script>
    <script src="https://code.jquery.com/jquery-3.4.1.min.js"></script>
    <script src="module.js"></script>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body ng-controller="myController">
    <div class="calendar">
      <div class="ancestor-2">
        <div class="ancestor-1">
          Calendar
        </div>
      </div>
    </div>
    <div class="widget">
      <div class="ancestor-2">
        <div class="ancestor-1">
          Not a calendar
        </div>
      </div>
    </div>
  </body>
</html>

CSS

.calendar {
  margin: 20px;
  padding: 20px;
  border: 2px solid blue;
}

.widget {
  margin: 20px;
  padding: 20px;
  border: 2px solid green;
}

JavaScript

(function () {
    'use strict';

    angular.module('app', []);

    angular.
        module('app')
        .controller('myController', ['$scope', function ($scope) {
            $(document).on('click', function ($event) {
                var nativeElement = $event.target;
                if ($(nativeElement).closest('.calendar').length) {
                    alert('Inside a calendar');
                }
                else {
                    alert('Outside a calendar');
                }
            });
        }])

})();