can-util/js/types/types

Use

can-util/js/types/types exports an object with placeholder functions that can be used to provide default types or test if something is of a certain type.

This is where the sausage of loose coupling modules takes place. Modules that provide a type will overwrite one or multiple of these functions so they take into account the new type.

For example, can-define/map/map might overwrite isMapLike to return true if the object is an instance of Map:

var types = require("can-util/js/types/types");
var oldIsMapLike = types.isMapLike;
types.isMapLike = function(obj){
  return obj instanceof DefineMap || oldIsMapLike.apply(this, arguments);
};
types.DefaultMap = DefineMap;