modifyAt method
If the given key
is present in the Map
, then modify its value
using update
and return the Map
.
If multiple keys equal to key
exist in the map, all of them are updated.
Otherwise, return None.
Implementation
Option<Map<K, V>> modifyAt(
Eq<K> eq,
V Function(V value) update,
K key,
) {
for (var entryKey in keys) {
if (eq.eqv(entryKey, key)) {
// At least one equal key exists in map.
return some({
for (var entry in entries)
entry.key:
eq.eqv(entry.key, key) ? update(entry.value) : entry.value
});
}
}
return const None();
}