Minor fixes to allow null frames internally

Author: rreusser

src/plot_api/plot_api.js

@@ -2399,6 +2399,8 @@ Plotly.animate = function(gd, frameOrGroupNameOrFrameList, animationOpts) {
             for(i = 0; i < trans._frames.length; i++) {
                 frame = trans._frames[i];
 
+                if(!frame) continue;
+
                 if(allFrames || frame.group === frameOrGroupNameOrFrameList) {
                     frameList.push({
                         type: 'byname',
@@ -2561,7 +2563,7 @@ Plotly.addFrames = function(gd, frameList, indices) {
         if(_hash[frame.name]) {
             // If frame is present, overwrite its definition:
             for(j = 0; j < _frames.length; j++) {
-                if(_frames[j].name === frame.name) break;
+                if((_frames[j] || {}).name === frame.name) break;
             }
             ops.push({type: 'replace', index: j, value: frame});
             revops.unshift({type: 'replace', index: j, value: _frames[j]});

src/plots/plots.js

@@ -1415,7 +1415,7 @@ plots.modifyFrames = function(gd, operations) {
                 break;*/
             case 'replace':
                 frame = op.value;
-                var oldName = _frames[op.index].name;
+                var oldName = (_frames[op.index] || {}).name;
                 var newName = frame.name;
                 _frames[op.index] = _hash[newName] = frame;
 

test/jasmine/tests/animate_test.js

@@ -579,3 +579,33 @@ describe('Test animate API', function() {
         });
     });
 });
+
+describe('null frames', function() {
+    'use strict';
+
+    var gd, mockCopy;
+
+    beforeEach(function(done) {
+        gd = createGraphDiv();
+
+        mockCopy = Lib.extendDeep({}, mock);
+
+        Plotly.plot(gd, mockCopy.data, mockCopy.layout).then(function() {
+            return Plotly.addFrames(gd, mockCopy.frames);
+        }).then(done);
+    });
+
+    afterEach(function() {
+        Plotly.purge(gd);
+        destroyGraphDiv();
+    });
+
+    it('should not break everything', function(done) {
+        gd._transitionData._frames.push(null);
+
+        Plotly.animate(gd, null, {
+            frame: {duration: 0},
+            transition: {duration: 0}
+        }).catch(fail).then(done);
+    });
+});