Multiple unrelated dataViewMappings for custom visuals Power BI Report Server

Question

There is a well-known problem connected with creating custom visuals for Power BI Report Sever - you can't create multiple unrelated dataViewMappings. It means that every field you put inside Fields must be related.

There have been a long-lasting request from users to add this feature.

However, it looks like Microsoft hasn't implemented it yet.

https://github.com/Microsoft/PowerBI-visuals/issues/251

I found a workaround - you can combine all your different tables in one and chain with a tableName key.

For example, you have a table A:

value1|value2|tableName
1|2|tableA
3|4|tableA

and a table B:

value3|tableName
a|tableB
b|tableB

You create a tableC by using M function Table.Combine({tableA, tableB}) or other technique. As a result, it looks like this:

value1|value2|value3|tableName
1|2|null|tableA
3|4|null|tableA
null|null|a|tableB
null|null|b|tableB

Then, inside your custom visual you implement the following function which parses the input:

    public parseOptionsToTables(options: VisualUpdateOptions) {
        var i: number;
        var j: number;

        var cntRows: number;
        var cntCols: number;
        var nameTable: string;
        var tempDict: {} = {};
        var tempVal: any;
        var colName: string;

        var cats: any = options.dataViews[0].table;

        this.tables = {};

        cntCols = cats.columns.length;
        cntRows = cats.rows.length;

        for (i = 0; i < cntRows; i++) {

            tempVal = null;
            colName = null;
            nameTable = null;
            tempDict = {};

            for (j = 0; j < cntCols; j++) {

                //for every row - check the TableName column and add to dict 

                tempVal = cats.rows[i][j];
                colName = cats.columns[j].displayName;


                if (colName == 'tableName') {

                    nameTable = tempVal;

                } else {

                    //add id not null
                    if (tempVal !== null) {

                        tempDict[colName] = tempVal;

                    }

                }

            }

            //push to dict

            this.tables[nameTable] = this.tables[nameTable] || [];
            this.tables[nameTable].push(this.deepcopy(tempDict));

        }

    }

As a result, it creates a this.tables object with your tableA and tableB inside.

Although it helps to solve the main problem, I can't get out of feeling of creating crutches. So, are there any other approaches to solve this problem more effeciently?

Hertfordshire