Sort by using Visuals API

Hey Zubair, and thanks very much for teaching me something new (to me!) 🙂

Being as I wasn't too informed on my previous post, I'd take what I say next with a grain of salt, but I haven't been able to find this myself in any previous (or current) projects and have deferred to using the visual header to manage.

I've never seen details on sort by column metadata for a field in the API, and if the sort values aren't in the dataset, they could not be used internally. It is likely that core visuals have more direct access to the data model as they are not sandboxed, or there are APIs that have not been promoted to the custom visuals SDK. 

If there isn't an API to bring in from core, something new on the visual host would be ideal for this, i.e.:

interface IVisualHost {
    ...
    applySort(columns: DataViewSortColumn[]) /* New */
}

interface DataViewSortColumn {
    queryName: string,
    direction: 'ascending' | 'descending'
}

(the param doesn't have to be an array, but sorting by multiple columns would be neat to achieve also)

Either way, I think it's better asked directly to the visuals team, or creating an issue in the GitHub repo for some dedicated assistance.

Regards,

Daniel