Toggle the inclusion of different series from chart through Legends

[VikrantRamesh]

I am using a Custom Legend that is rendered in JS and I am trying to introduce interactivity through vega signals. I want the following interactive behaviour:

• When a legend is clicked, that particular series is excluded from the chart and the rest of the chart is recalculated and rendered.

Example (Expected Output):

What I tried:
I added a filter on the data source to filter out that particular field's color. But this doesnt re-render the chart as expected as it just hides the visibility of the series from the chart. I am looking for any other possible solution for this issue.

        dataSource.transform.push({
          type: 'filter',
          expr: `indexof(${this.HIDDEN_SERIES_SIGNAL}, datum.${this.COLOR_FIELD}) === -1`
        });

output:

[domoritz]

dataSource.transform.push({
          type: 'filter',
          expr: `indexof(${this.HIDDEN_SERIES_SIGNAL}, datum.${this.COLOR_FIELD}) === -1`
        });

will not update reactively since js is not reactive. You have to instead explicitly create a signal/param for the filtered value and set that via the Vega View API if you want a legend that is external to the chart. If you use a native legend, you might be able to directly depend on the signal/param the legend defines.