Deneb | Vega-Lite tooltip issue

[Doug7983]

With much help from @giammariam , I have a Deneb custom visual that is exactly what I want--except for the tooltip. Deneb is displaying the tooltip for the highlighted null data point as 0.0%. I would expect to see a blank. 

Here is the relevant part of the tooltip block from my spec:

{
"field": "Growth (month over year-ago month)",
"type": "quantitative",
"format": ".1%"
},

This works great except for the display of the last data point, which again should be blank, null, "n/a" or something of the sort.

Appreciate any help. 

[giammariam]

Ha, thanks @Doug7983. Feel free to reach out anytime. 

[Doug7983]

Hey @giammariam, thanks for the response. Security policies prevent me from sharing a pbix in that manner. Here's the thread where you helped me with the spec.

Thank you.

[giammariam · Accepted solution]

Thanks @Doug7983, try the following:

1. In the top transform array add the following: 

    ,
    {
      "calculate": "isValid(datum['Growth (MoYaM)']) ? format(datum['Growth (MoYaM)'], '.1%') : ''",
      "as": "Growth (MoYaM) Tooltip"
    },
    {
      "calculate": "isValid(datum['Growth (WDC)']) ? format(datum['Growth (WDC)'], '.1%') : ''",
      "as": "Growth (WDC) Tooltip"
    }

Note - if you want it to show null or n/a, replace the '' with null or 'n/a'. As it is currently, it will just be blank

2. Update the tooltip to the following:

      "tooltip": [
        {"field": "Category", "type": "nominal"},
        {"field": "Date", "type": "temporal"},
        {"field": "Growth (MoYaM) Tooltip", "title": "Growth (MoYaM)", "type": "nominal"},
        {"field": "Growth (WDC) Tooltip", "title": "Growth (WDC)", "type": "nominal"}
      ],

Let me know if this works

[Doug7983]

You're incredible, @giammariam . Thanks so much. 

[giammariam]

Hey @Doug7983, thanks for the tag. Can you either send me your .pbix  (here's how), or send me the link to the post where I helped you originally? Happy to dive back into the spec and get this straight for you, I would just would need to refamiliarize myself with what I did.