allow callback or userCallback in the time scale

diff --git a/src/scales/scale.time.js b/src/scales/scale.time.js
index b57a09113961531ba8a8326e9013b89ae236bb25..1a2fccf0debea1d3716a58a64bd49104ef3922d8 100644 (file)
--- a/src/scales/scale.time.js
+++ b/src/scales/scale.time.js
@@ -299,9 +299,11 @@ module.exports = function(Chart) {
                // Function to format an individual tick mark
                tickFormatFunction: function tickFormatFunction(tick, index, ticks) {
                        var formattedTick = tick.format(this.displayFormat);
+                       var tickOpts = this.options.ticks;
+                       var callback = helpers.getValueOrDefault(tickOpts.callback, tickOpts.userCallback);
 
-                       if (this.options.ticks.userCallback) {
-                               return this.options.ticks.userCallback(formattedTick, index, ticks);
+                       if (callback) {
+                               return callback(formattedTick, index, ticks);
                        } else {
                                return formattedTick;
                        }