DAX Lib is a website designed to distribute libraries of DAX user-defined functions (UDF). Similar to NuGet, DAX Lib provides a centralized platform where users can discover, share, and download reusable DAX function libraries to enhance their Fabric, Power BI, and Analysis Services semantic models.

DAX libraries

A DAX library is a collection of DAX user-defined functions that can be reused across different semantic models, promoting best practices and reducing duplication of effort.

Functions designed for DAX libraries

A DAX user-defined function is candidate for a library if it is model-independent, which means that it has no references to specific tables, columns, or measures within a particular model. When a function has direct dependencies on model elements, it is not suitable for inclusion in a DAX library and must be refactored to remove those dependencies.

Example of a model-independent function, good candidate for a DAX library:

    FUNCTION RangeLookup = (
            search : SCALAR VAL,
            lookupTable : TABLEREF EXPR,
            colMin : COLUMNREF EXPR,
            colMax : COLUMNREF,
            colTarget : COLUMNREF
        ) =>
        SELECTCOLUMNS (
            FILTER ( 
                lookupTable, 
                colMin <= search && colMax > search 
            ),
            "@Result", colTarget
        )

Example of a model-dependent function, which could be defined in a semantic model to simplify the consumption of a generic function imported from a DAX library:

    FUNCTION PriceLookup = (
            search : SCALAR VAL
        ) =>
        RangeLookup (
            search,
            'Price Range',
            'Price Range'[Min],
            'Price Range'[Max],
            'Price Range'[Range]
        )