mapOr<U> method

Option<U> mapOr<U>(
  1. U orValue,
  2. U mapFn(
    1. T
    )
)

Maps this Option<T> to an Option<U> using the given function with the held value if this Option<T> is Some. Otherwise returns the provided orValue as Some(orValue).

Values passed for orValue are eagerly evaluated. Consider using Option.mapOrElse() to provide a default that will not be evaluated unless this Option is None.

Option<int> a = Some(1);
Option<int> b = None();

print(a.mapOr(5, (val) => val + 1).unwrap()); // prints: 2
print(b.mapOr(5, (val) => val + 1).unwrap()); // prints: 5

Note: Unlike Rust's Option::map_or(), this method returns an Option value. Given that Option.map() returns the mapped Option it just made sense for this method to do the same.

See also: Rust: Option::map_or()

Implementation

Option<U> mapOr<U>(U orValue, U Function(T) mapFn) => switch (this) {
	Some(:T v) => Some(mapFn(v)),
	None() => Some(orValue)
};