Checks if an Optional is Optional.None. Acts as a type guard.
The Optional.Base type to check.
The Optional to check.
true if the Optional is Optional.None, false otherwise.
true
false
const optionalValue = Optional.none as Optional<number>;if (Optional.isNone(optionalValue)) { // Type narrowed to None assert.ok(true); // optionalValue is None} Copy
const optionalValue = Optional.none as Optional<number>;if (Optional.isNone(optionalValue)) { // Type narrowed to None assert.ok(true); // optionalValue is None}
Checks if an Optional is Optional.None. Acts as a type guard.