dart:collection

containsValue method

bool containsValue(Object value)

Returns true if this map contains the given value.

Returns true if any of the values in the map are equal to value according to the == operator.

Source

bool containsValue(Object value) {
  bool found = false;
  int initialSplayCount = _splayCount;
  bool visit(_SplayTreeMapNode node) {
    while (node != null) {
      if (node.value == value) return true;
      if (initialSplayCount != _splayCount) {
        throw new ConcurrentModificationError(this);
      }
      if (node.right != null && visit(node.right)) return true;
      node = node.left;
    }
    return false;
  }

  return visit(_root);
}