Defaults tooltip option not working at all

[Kilazur]

Expected Behavior

When setting default options for tooltips, they should be taken into account.

Current Behavior

The custom default options are completely ignored.

Possible Solution

As far as I can tell, it's either just a small overlooked issue on Chart.js's side, or I don't understand how to set these defaults. A possible solution to that would be some more "defaults configuration" examples in the documentation, because tbh this point is a little confusing :)

Steps to Reproduce

http://jsfiddle.net/a40dhzsm/1/

Context

I'm simply trying to add a "%" symbol at the end of tooltip labels.

Environment

• Chart.js version: 3.5.1
• Browser name and version: Firefox 93.0 / Chrome 94.0

[elinake]

I'm not sure setting those as defaults is possible or optimal. When I added the options to chart it worked: http://jsfiddle.net/elinakeranen/2v31hec4/21/

options: {
         plugins: {
          tooltip: {
           enabled: true,
           intersect: false,
           mode: 'nearest',
           callbacks: {
             title: () => 'title',
             label: (item) => item.parsed + '%'
           },
         }
         }
       },

[LeeLenaleee]

It is possible, if you change the type to bar it works fine, reason I expect it not working for pie/doughnut charts is that chart.js overrides the default behaviour (can be seen by logging Chart.overrides.doughnut).

Guess it might be better user experience to also override the defaults if a default is set.

[etimberg]

@LeeLenaleee has the correct answer. The pie/doughnut charts have overrides which are used first so the default you've specified is not used. I'm not entirely sure what the best fix is here. We could try and make the docs clearer to indicate that overrides are specified. I think it could be surprising if setting global defaults also overrode chart defaults though perhaps we could expose a method that did that for those who wanted it.