robustify tickformatstops supplydefaults

Author: alexcjohnson

src/plots/cartesian/tick_label_defaults.js

@@ -83,8 +83,10 @@ function getShowAttrDflt(containerIn) {
 }
 
 function tickformatstopsDefaults(tickformatIn, tickformatOut) {
-    var valuesIn = tickformatIn.tickformatstops || [],
-        valuesOut = tickformatOut.tickformatstops = [];
+    var valuesIn = tickformatIn.tickformatstops;
+    var valuesOut = tickformatOut.tickformatstops = [];
+
+    if(!Array.isArray(valuesIn)) return;
 
     var valueIn, valueOut;
 
@@ -101,6 +103,4 @@ function tickformatstopsDefaults(tickformatIn, tickformatOut) {
 
         valuesOut.push(valueOut);
     }
-
-    return valuesOut;
 }

test/jasmine/tests/tickformatstops_test.js

@@ -289,4 +289,19 @@ describe('Test tickformatstops:', function() {
         .then(done);
     });
 
+    it('doesn\'t fail on bad input', function(done) {
+        var promise = Plotly.plot(gd, mockCopy.data, mockCopy.layout);
+
+        [1, {a: 1, b: 2}, 'boo'].forEach(function(v) {
+            promise = promise.then(function() {
+                return Plotly.relayout(gd, {'xaxis.tickformatstops': v});
+            }).then(function() {
+                expect(gd._fullLayout.xaxis.tickformatstops).toEqual([]);
+            });
+        });
+
+        promise
+        .catch(fail)
+        .then(done);
+    });
 });