orElseThrow method

T orElseThrow()

If a value is present, returns the value, otherwise throws InvalidArgumentException.

Returns the non-null value described by this Optional.

Throws InvalidArgumentException if no value is present.

Example

Optional<String> name = Optional.of("Liam");
Optional<String> empty = Optional.empty();

print(name.orElseThrow()); // "Liam"

try {
  print(empty.orElseThrow());
} catch (e) {
  print("Error: $e"); // Error: Bad state: No value present
}

// Preferred over get() method
String safeName = name.orElseThrow(); // Clear intent

Implementation

T orElseThrow() {
  if (_value == null) {
    throw InvalidArgumentException('No value present');
  }
  return _value as T;
}