The cmp Package

The cmp package, added in Go 1.21, gives you a generic vocabulary for ordering values. It defines the Ordered constraint that slices.Sort and friends rely on, a pair of comparison functions that handle floating-point NaN cleanly, and (since Go 1.22) cmp.Or for picking the first non-zero value out of a list. The package is small, with three top-level functions and one constraint, but it cleans up a class of code that used to require either reflection or hand-written Less functions for every type. Most production Go projects pick it up the day they upgrade past 1.21, because it removes boilerplate from every sort and every "pick a default" expression.