Union function using Turf.js and Leaflet Geodesy

HTML

<script src="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js"></script>
<link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.css">
<script src="https://api.mapbox.com/mapbox.js/plugins/leaflet-geodesy/v0.1.0/leaflet-geodesy.js"></script>
<script src="https://api.mapbox.com/mapbox.js/plugins/turf/v2.0.2/turf.min.js"></script>
<div id="map"></div>

CSS

#map {
  height: 500px;
}

JavaScript

var parentCoordinates=[
    [
        32.05898221582174,
        -28.31004731142091
    ],
    [
        32.05898221582174,
        -28.308044824292978
    ],
    [
        32.06134255975485,
        -28.308044824292978
    ],
    [
        32.06134255975485,
        -28.31004731142091
    ],
    [
        32.05898221582174,
        -28.31004731142091
    ]
];

var childCoordinates=[
  [
    32.059904895722866,
    -28.30970726909422
  ],
  [
    32.059904895722866,
    -28.308743809931784
  ],
  [
    32.06089194864035,
    -28.308743809931784
  ],
  [
    32.06089194864035,
    -28.30970726909422
  ],
  [
    32.059904895722866,
    -28.30970726909422
  ]
];

var parentPolygon = turf.polygon([parentCoordinates]);

var inside = true;
childCoordinates.forEach(function(coordinates) {
    point = turf.point(coordinates);
    if (!turf.inside(point, parentPolygon)){
      alert("Oh no! "+ coordinates + " isn't in polygon");
      inside = false;
    }
});

alert("Child polygon inside parent polygon ? " + inside);