Migrate topojson.filter with spherical coordinate-system from previous API

[lorenzobruni]

Hi,

I need some help with moving to the new API v3 of Topojson.

In my working code I have the following line:

topojson.filter(topology, { "coordinate-system": "spherical" } );

How can I do the same in the new API v3?
By looking at the documentation I understand that the new topojson.filter(topology[, filter]) accepts a filter function rather than an object with a "coordinate-system"?

Thanks for any help or advice.