make trace uid accept numbers

Author: etpinard

src/plots/plots.js

@@ -563,7 +563,10 @@ function getTraceUids(oldFullData, newData) {
     }
 
     for(i = 0; i < len; i++) {
-        if(tryUid(newData[i].uid, i)) continue;
+        var newUid = newData[i].uid;
+        if(typeof newUid === 'number') newUid = String(newUid);
+
+        if(tryUid(newUid, i)) continue;
         if(i < oldLen && tryUid(oldFullInput[i].uid, i)) continue;
         setUid(Lib.randstr(seenUids), i);
     }

test/jasmine/tests/plots_test.js

@@ -153,6 +153,26 @@ describe('Test Plots', function() {
 
             testSanitizeMarginsHasBeenCalledOnlyOnce(gd);
         });
+
+        it('should accept trace uids as non-empty strings or numbers', function() {
+            var gd = {
+                data: [{}, {uid: false}, {uid: 'my-id'}, {uid: ''}, {uid: 0}, {uid: 2}]
+            };
+            supplyAllDefaults(gd);
+
+            var traceUids = gd._fullLayout._traceUids;
+            expect(traceUids.length).toBe(6, '# of trace uids');
+            expect(traceUids[2]).toBe('my-id');
+            expect(traceUids[4]).toBe('0');
+            expect(traceUids[5]).toBe('2');
+
+            var indicesOfRandomUid = [0, 1, 3];
+            indicesOfRandomUid.forEach(function(ind) {
+                var msg = 'fullData[' + ind + '].uid';
+                expect(typeof traceUids[ind]).toBe('string', msg + 'is a string');
+                expect(traceUids[ind].length).toBe(6, msg + 'is of length 6');
+            });
+        });
     });
 
     describe('Plots.supplyLayoutGlobalDefaults should', function() {