computeIfAbsent method

V computeIfAbsent(
  1. K key,
  2. V ifAbsent(
    1. K key
    )
)

Implementation

V computeIfAbsent(K key, V Function(K key) ifAbsent) {
  if (!containsKey(key)) {
    this[key] = ifAbsent(key);
  }
  return this[key]!;
}