Which is the best way to work with two different parameters bound to the legend?

[eduardoraygoza-quidel]

I have a line chart and I want to group the lines using different fields. I've achieved this using a selection parameter. Example here

If I select a group in the legend and then switch fields the chart goes blank. I understand that it's because the signal holds the values selected using the previous field and that I just need to select the groups in the new legend to show the lines, but I want to show all the lines (clear the values in the signal) when I change fields.

I thought about dividing the visualization in layers, create a param in each one to hold each legend values and set the whole visualization opacity to 0 if it's field is not selected, but the signals are bound to the same legend, so clicking on it adds or removes values from both signals. I tried setting "toggle": "dimention == 'dimentionX'" to just add values from their respective group, but toggle only works when working with multiple values, which is not quite what I need.

Is this the best way to handle this?
Would it be better to switch to full Vega?

Thanks!

[domoritz]

Does this work better if you instead change your data to long form (tidy from) and then switch the data using a selection over a field that switches between the two datasets?

[eduardoraygoza-quidel]

I hope I understood that correctly, following your advice here's what I did:

1. Added a fold transformation to change the data to long form
2. Added a filter on the key field to keep only the field I select using the combobox
3. changed the color property to use the value field

I get the exact same behavior, values from both fields can be added to the signal bound to the legend, am I missing something?

Here's the updated chart

Here's also the chart divided in layers as I mentioned using this approach. This is the closest I've gotten to what I want to achieve, but clicking on the legend, even when the dimention selected is 2, it operates on signal 1. Example

Any ideas are appreciated!

[eduardoraygoza-quidel]

I've managed to solve it with help from another forum, here's the solution:

1. Compile Vega-Lite to Vega
2. To any signal that listens to view-click event add an additional dimention event to the listener, and in that case return null

Solved example

Kudos to Marco Liberati