# macro()
The macro method lets you register custom methods
collect().macro('uppercase', function () {
return this.map(item => item.toUpperCase());
});
const collection = collect(['a', 'b', 'c']);
collection.uppercase();
collection.all();
// ['A', 'B', 'C']
Note that the
macro
method returnsundefined
, and therefore it is not possible to use it within a chain of methods.