make uid of expanded trace valid alpha-numerical hashes

Author: etpinard

src/plots/plots.js

@@ -657,9 +657,9 @@ plots.supplyDataDefaults = function(dataIn, dataOut, layout) {
                 var expandedTrace = expandedTraces[j],
                     fullExpandedTrace = plots.supplyTraceDefaults(expandedTrace, cnt, layout);
 
-                // mutate uid w.r.t to expanded index to promote consistency
-                // between update calls.
-                expandedTrace.uid = fullExpandedTrace.uid = fullTrace.uid + '-' + j;
+                // mutate uid here using parent uid and expanded index
+                // to promote consistency between update calls
+                expandedTrace.uid = fullExpandedTrace.uid = fullTrace.uid + j;
 
                 // add info about parent data trace
                 fullExpandedTrace.index = i;

test/jasmine/tests/transforms_test.js

@@ -117,7 +117,7 @@ describe('one-to-one transforms:', function() {
             assertDims([3]);
 
             var uid = data[0].uid;
-            expect(gd._fullData[0].uid).toEqual(uid + '-0');
+            expect(gd._fullData[0].uid).toEqual(uid + '0');
 
             done();
         });