I don’t know why. Maybe the typings for it are just fucking bad. Or maybe d3 is very hard to use “correctly”, but still works most of the time even if invoked incorrectly (I doubt that). Or maybe d3 is so complex that the typings need to be complex, too, even if you don’t use the complexity (the type retured from selectAll has four type parameters, half of which are undefined by default, the other half, null).