How to update chart when data prop changes?

[chipit24]

I've read through the discussions in the following issues but they did not help resolve my problem: #10, #7.

Here is an example on my issue on Code Sandbox: https://codesandbox.io/s/6w9mjky30w.

As you can see, I use buttons to change the data prop that is passed to vue-chart. The data is set to a new object if a different button is pressed, which is verified by the watcher I've set up.

If I'm passing a new data object to vue-chart, why, then, does the chart not update?