Add additional casting

Author: rreusser

src/plot_api/plot_api.js

@@ -2327,7 +2327,11 @@ Plotly.animate = function(gd, frameOrGroupNameOrFrameList, animationOpts) {
             var newFrame = trans._currentFrame = trans._frameQueue.shift();
 
             if(newFrame) {
-                gd._fullLayout._currentFrame = newFrame.name;
+                // Since it's sometimes necessary to do deep digging into frame data,
+                // we'll consider it not 100% impossible for nulls or numbers to sneak through,
+                // so check when casting the name, just to be absolutely certain:
+                var stringName = newFrame.name ? newFrame.name.toString() : null;
+                gd._fullLayout._currentFrame = stringName;
 
                 trans._lastFrameAt = Date.now();
                 trans._timeToNext = newFrame.frameOpts.duration;
@@ -2349,7 +2353,7 @@ Plotly.animate = function(gd, frameOrGroupNameOrFrameList, animationOpts) {
                 });
 
                 gd.emit('plotly_animatingframe', {
-                    name: newFrame.name,
+                    name: stringName,
                     frame: newFrame.frame,
                     animation: {
                         frame: newFrame.frameOpts,

test/jasmine/tests/command_test.js

@@ -444,6 +444,12 @@ describe('Plots.computeAPICommandBindings', function() {
             expect(result).toEqual([{type: 'layout', prop: '_currentFrame', value: 'framename'}]);
         });
 
+        it('treats numeric frame names as strings', function() {
+            var result = Plots.computeAPICommandBindings(gd, 'animate', [[8]]);
+
+            expect(result).toEqual([{type: 'layout', prop: '_currentFrame', value: '8'}]);
+        });
+
         it('binds to nothing for a multi-frame animate command', function() {
             var result = Plots.computeAPICommandBindings(gd, 'animate', [['frame1', 'frame2']]);