Forum Discussion

Schizzomarino's avatar
Schizzomarino
Advocate I
6 years ago
Solved

Problem using "d3-array".rollup (and it spread argument) in a Power BI Custom Visual

Hello to you all, I am hoping someone will have a solution for a problem I have encountered using "d3-array" in a custom visual for Power BI. I have been using d3 v5 as it's got really nice data mu...
  • jppp's avatar
    jppp
    6 years ago

    Hi Schizzomarino ,

     

    Sorry, but I took a shot before trying it myself. But if I change the key attribute to ...key: any[] I can get your code working.

    I do realise that the typing are a bit off now, but looks like TypeScript doesn't work correctly with this type of parameter binding.

    But the most important thing: it compiles!

     

    -JP

Schizzomarino's avatar
Schizzomarino
Advocate I
6 years ago

Thanks jppp ,

I had not noticed this... Just goes to show how I still need to learn about definitions in typescript

So looking at the type definition I found this

/* 

@param a The array to group. 
@param reduce The reduce function.  
@param key The key function.
*/
export function rollup<TObject, TKey, TReduce>(a: Iterable<TObject>, reduce: (value: TObject[]) => TReduce, key: (value: TObject) => TKey) : Map<TKey, TReduce>;
 
Unfortunately I can't figure where to insert the spread operator here, would someone know how to change it, so the above line from the type definitions file provides the third argument as a spread one (key/TReduce)?
 
Thanks again JP
 
Daniel
jppp's avatar
jppp
Continued Contributor
6 years ago

Hi Schizzomarino ,

 

You can adjust your local version in the node_modules/@types/d3-array folder.

And I think you only need to add the spread '...' before the key parameter:

export function rollup<TObject, TKey, TReduce>(a: Iterable<TObject>, reduce: (value: TObject[]) => TReduce, ...key: (value: TObject) => TKey) : Map<TKey, TReduce>;

 

-JP

  • Schizzomarino's avatar
    Schizzomarino
    Advocate I
    6 years ago

    Hi jppp ,

    I had tried that amongst a whole pletora of other combinations; but Visual Studio will not compile this... I get the following tooltip:

    I have tried so many variations but can't find one that works; and I found this discussion on this:
    https://stackoverflow.com/questions/51737041/mapping-generic-spreaded-argument-types-in-typescript

    For now I can't quite wrap my head around the technical topic in the above thread... I finsd it rather complicated, probably why it has taken two years, so far, to not have it fixed  :-0

    Would anyone know how to get this to work? It would be great after two years to find this solution and update the types mapping for d3-array in the git repository

     

    Thanks again jppp for pointing me in the right direction, but before I set yours as the correct answer I want to see if anyone has code that will work to define spread arguments when exporting types definitions in Typescript

    • jppp's avatar
      jppp
      Continued Contributor
      6 years ago

      Hi Schizzomarino ,

       

      Sorry, but I took a shot before trying it myself. But if I change the key attribute to ...key: any[] I can get your code working.

      I do realise that the typing are a bit off now, but looks like TypeScript doesn't work correctly with this type of parameter binding.

      But the most important thing: it compiles!

       

      -JP

      • Schizzomarino's avatar
        Schizzomarino
        Advocate I
        6 years ago

        Thanks so much jppp 
        That worked!

         

        If "any[]" (and "any" for that matter) will enable loose type setting but (seem to) work flawlessly, what is stopping everyone from creating such loose typescript definitions?