Add custom control button to leafletmap

controllers.js

        //Add center result control button
        L.easyButton({
            states: [{
                stateName: 'zoom-to-forest',
                icon:      'glyphicon glyphicon-screenshot',
                title:     'Center map to heat results',
                onClick: function(btn, map) {
                    if (typeof $scope.heatLayer != 'undefined'
                            && typeof $scope.maxGlobalHeat != 'undefined') {
                        map.setView($scope.maxGlobalHeat, 10);
                    }
                }
             }]
         }).addTo(map);