associateBy<K> method
Returns a Map containing the elements from the collection indexed by
the key returned from keySelector
function applied to each element.
If any two elements would have the same key returned by keySelector
the
last one gets added to the map.
Implementation
Map<K, E> associateBy<K>(K Function(E element) keySelector) {
var map = <K, E>{};
for (var current in this) {
map[keySelector(current)] = current;
}
return map;
}