Currently {{compare}} (for any non-CLJS IComparable) types only accepts primitives (numbers, bool, string, array) and forwards them to {{goog.array.defaultCompare}} (which is just a {{ return a > b ? 1 : a < b ? -1 : 0 }} ).
Though, the standard defines anything with a {{valueOf}} can be compared:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators#Relational_operators
since {{valueOf}} should return one of these primitves. Ie this works:
(let [x0 #js{:x 1, :valueOf #(-> 1)}
x1 #js{:x 2, :valueOf #(-> 2)}
dc garr/defaultCompare]
(list (dc x0 x1) (dc x1 x0) (dc x1 x1)))
We should allow this, ie. instead of:
:else
(if (and (or (string? x) (array? x) (true? x) (false? x))
(identical? (type x) (type y)))
(garray/defaultCompare x y)
(throw (js/Error. (str "Cannot compare " x " to " y))))
do a:
(if (and (or (string? x) (array? x) (true? x) (false? x)
(and (js-in "valueOf" x) (js-in "valueOf" y)))
(identical? (type x) (type y)))
(garr/defaultCompare x y)
(throw (js/Error. (str "Cannot compare " x " to " y))))
We should also give {{js-in}} a boolean tag.
