How to hide select series from legend in HTML5 charts?

Q: Legend settings for selected series should be hidden based on a parameter selection. How should we achieve that?

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A: You can use a series property contributor that sets the showInLegend for each series.

The solution is rather convoluted because series contributors can only access bucket and measure values and cannot directly reference dataset values such as parameters. For that reason a dummy column level is required to make the values available for the chart.

For example:

<dataaxis axis="Columns">
    <axislevel name="root">
        <labelexpression>"root"</labelexpression>
        <axislevelbucket>
            <bucketexpression>""</bucketexpression>
     <bucketproperty name="showCategory1">
                ($P{showSeries}.indexOf("All") != -1)
                 || ($P{showSeries}.indexOf("Category1") != -1)
            </bucketproperty>
            <bucketproperty name="showCategory2">
                ($P{showSeries}.indexOf("All") != -1)
                 || ($P{showSeries}.indexOf("Category2") != -1)
            </bucketproperty>
            <bucketproperty name="showCategory3">
                ($P{showSeries}.indexOf("All") != -1)
                 || ($P{showSeries}.indexOf("Category3") != -1)
            </bucketproperty>
        </axislevelbucket>
    </axislevel>
</dataaxis>

and

<hc:series name="Category1">
    <hc:contributor name="SeriesProperty">
        <hc:contributorproperty name="showInLegend" value="root.showCategory1" valuetype="Bucket" />
    </hc:contributor>
</hc:series>
<hc:series name="Category2">
    <hc:contributor name="SeriesProperty">
        <hc:contributorproperty name="showInLegend" value="root.showCategory2" valuetype="Bucket" />
    </hc:contributor>
</hc:series>
<hc:series name="Category3">
    <hc:contributor name="SeriesProperty">
        <hc:contributorproperty name="showInLegend" value="root.showCategory3" valuetype="Bucket" />
    </hc:contributor>
</hc:series>