# Map<K, V>.unmodifiable constructor

Map<K, V>.unmodifiable(Map other)

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

The keys must all be instances of `K` and the values of `V`. The `other` map itself can have any type.

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

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

## Implementation

    external factory Map.unmodifiable(Map other);