Creating SelectionIds when you have two categories in your DataViewMapping

[paul-maessen]

Hi,

I do have a question about the creation of SelectionIds when your DataViewMapping has 2 categories.

The dataRoles and dataViewMapping:

{
    "dataRoles": [
        {
            "displayName": "Cat 1",
            "name": "cat1",
            "kind": "Grouping"
        },
        {
            "displayName": "Cat 2",
            "name": "cat2",
            "kind": "Grouping"
        },
        {
            "displayName": "Values",
            "name": "values",
            "kind": "Measure"
        }
    ],
    "dataViewMappings": [
        {
            "categorical": {
                "categories": {
                    "for": {
                        "in": "cat1"
                    },
                    "for": {
                        "in": "cat2"
                    }
                },
                "values": {
                    "select": [
                        {
                            "bind": {
                                "to": "values"
                            }
                        }

                }
            }
        }
    ]
}

My question is now how I can create the SelectionIds for this situation:

Is the following assumption correct?

// categories
const categories = dataView.categorical.categories;


// get count of category elements
const categoriesCount = categories[0].values.length;

// iterate all categories to generate selection and create button elements to use selections
for (let categoryIndex = 0; categoryIndex < categoriesCount; categoryIndex++) {

    const categorySelectionId = this.host.createSelectionIdBuilder()
        .withCategory(categories[0], categoryIndex) 
        .withCategory(categories[1], categoryIndex) 
        .createSelectionId();
}

Thanks in advance,

Regards

Paul

@dm-p

[dm-p · Accepted solution]

Hi @paul-maessen,

Yes, I believe so. It should be fairly easy to tell from the resulting SelectionId if it has both categories and indices in the resulting map though, if you wanted to try it out.

The only thing I might do differently (and this is more of a personal preference and has no net effect on your code) is swap the for with a forEach and a fat arrow function, e.g.:

categories[0].values.forEach((v, vi) => {
    const categorySelectionId = this.host.createSelectionIdBuilder()
        .withCategory(categories[0], vi)
        .withCategory(categories[1], vi)
        .createSelectionId();
});

Cheers,

Daniel

[paul-maessen]

Hi @dm-p 

Thanks for the answer and the confirmation.

I normally also would use a forEach, but this code I copied from the documentation from Microsoft and modified it 🙂

Regards

Paul