Dynamically Change Column Type based on Column Name/Type from another table

Hi KNP   ,
funny, my understanding of Anonymous s request is just about a topic that I intended to blog about for some time (but too busy currently). Done that in some customer projects as well lately and it works really good. I find it especially useful when working with dataflows.
But I'm attaching the file here.
The transformations are done using this function:

(TableToBeTransformed as table, TableName as text) =>
    let
        FilterMatchingTableFromMapping = Table.SelectRows(ColumnMapping, each [Table] = TableName),
        TablesColumnNames = Table.FromColumns({Table.ColumnNames(TableToBeTransformed)}),
        FilterRelevantColumns = Table.NestedJoin(
            FilterMatchingTableFromMapping,
            {"old"},
            TablesColumnNames,
            {"Column1"},
            "TablesColumnNames",
            JoinKind.Inner
        ),
        RenameColumns = Table.RenameColumns(
            TableToBeTransformed,
            List.Transform(Table.ToRecords(FilterRelevantColumns), each {_[old], _[new]})
        ),
        #"Changed Type" = Table.TransformColumnTypes(
            RenameColumns,
            List.Transform(
                Table.ToRecords(FilterRelevantColumns),
                each {_[new], fnReplaceTypes(_[Type])}
            )
        )
    in
        #"Changed Type"

Hope this is what you've been looking for.