fix(enableColumnResizing): enableColumnResizing accumulates watchers with each table $digest cycle (#5933)

* Fix for column resizer watchers accumulating.

* Added declarations for resizerScopes and resizers array.

* Added unit test to ensure watchers get destroyed.

Author: jedancona

src/features/resize-columns/js/ui-grid-column-resizer.js

@@ -199,7 +199,9 @@
       compile: function() {
         return {
           post: function ($scope, $elm, $attrs, uiGridCtrl) {
-            var grid = uiGridCtrl.grid;
+            var grid = uiGridCtrl.grid,
+              resizerScopes = [],
+              resizers = [];
 
             if (grid.options.enableColumnResizing) {
               var columnResizerElm = $templateCache.get('ui-grid/columnResizer');
@@ -211,13 +213,9 @@
                 rtlMultiplier = -1;
               }
 
-              var displayResizers = function(){
+              var displayResizers = function () {
 
-                // remove any existing resizers.
-                var resizers = $elm[0].getElementsByClassName('ui-grid-column-resizer');
-                for ( var i = 0; i < resizers.length; i++ ){
-                  angular.element(resizers[i]).remove();
-                }
+                removeResizers();
 
                 // get the target column for the left resizer
                 var otherCol = uiGridResizeColumnsService.findTargetCol($scope.col, 'left', rtlMultiplier);
@@ -227,18 +225,29 @@
                 if (otherCol && renderContainer.visibleColumnCache.indexOf($scope.col) !== 0 && otherCol.colDef.enableColumnResizing !== false) {
                   var resizerLeft = angular.element(columnResizerElm).clone();
                   resizerLeft.attr('position', 'left');
-
                   $elm.prepend(resizerLeft);
-                  $compile(resizerLeft)($scope);
+                  $compile(resizerLeft)(resizerScopes[resizerScopes.push($scope.$new()) - 1]);
                 }
 
                 // Don't append the right resizer if this column has resizing disabled
                 if ($scope.col.colDef.enableColumnResizing !== false) {
                   var resizerRight = angular.element(columnResizerElm).clone();
                   resizerRight.attr('position', 'right');
-
                   $elm.append(resizerRight);
-                  $compile(resizerRight)($scope);
+                  $compile(resizerRight)(resizerScopes[resizerScopes.push($scope.$new()) - 1]);
+                }
+              };
+
+              var removeResizers = function() {
+                // remove any existing resizer scopes.
+                for (var x = resizerScopes.length - 1; x >= 0; x--) {
+                  resizerScopes[x].$destroy();
+                  resizerScopes.splice(x);
+                }
+                // remove any existing resizer elements.
+                resizers = $elm[0].getElementsByClassName('ui-grid-column-resizer');
+                for (var i = resizers.length - 1; i >= 0; i--) {
+                  angular.element(resizers[i]).remove();
                 }
               };
 
@@ -250,7 +259,10 @@
 
               var dataChangeDereg = grid.registerDataChangeCallback( waitDisplay, [uiGridConstants.dataChange.COLUMN] );
 
-              $scope.$on( '$destroy', dataChangeDereg );
+              $scope.$on( '$destroy',function() {
+                dataChangeDereg();
+                removeResizers();
+              });
             }
           }
         };

src/features/resize-columns/test/resizeColumns.spec.js

@@ -93,6 +93,16 @@ describe('ui.grid.resizeColumns', function () {
     });
   });
 
+  describe('destroying header cell',function(){
+    it('should have 0 watchers after destroy',function(){
+      var secondCol = $(grid).find('[ui-grid-header-cell]:nth-child(1)');
+      secondCol.parent().scope().$destroy();
+      var numWatchers = secondCol.scope().$$watchers.length;
+
+      expect(numWatchers).toEqual(0);
+    });
+  });
+
   describe('setting enableColumnResizing to false', function () {
     it('should result in no resizer elements being attached to the column', function () {
       $scope.gridOpts.enableColumnResizing = false;