Map<K, V>.unmodifiableOf constructor

  1. @Since.new("3.13")
Map<K, V>.unmodifiableOf(
  1. Map<K, V> other
)

Creates an unmodifiable hash-based map containing the entries of other.

The map requires the keys to implement compatible operator== and hashCode. The created map iterates keys in a fixed order, preserving the order provided by other.

The resulting map behaves like the result of Map.of, except that the map returned by this constructor is not modifiable.

final planets = <int, String>{1: 'Mercury', 2: 'Venus', 3: 'Earth'};
final unmodifiableMap = Map.unmodifiableOf(planets);
unmodifiableMap[4] = 'Mars'; // Throws

Implementation

@Since("3.13")
factory Map.unmodifiableOf(Map<K, V> other) = Map<K, V>.unmodifiable;