Function orElse

orElse<O extends Optional.Base, const O2 extends Optional.Base>(
optional: O,
alternative: O2,
): O | O2
Returns the Optional if it is Some, otherwise returns the alternative.

Provides a way to chain Optional operations with fallback values. This is particularly useful for implementing default behavior or cascading lookups. Supports both direct usage and curried form for functional composition.
Type Parameters
- O extends Optional.Base
  The input Optional.Base type.
- const O2 extends Optional.Base
Parameters
- optional: O
  The Optional to check.
- alternative: O2
  The alternative Optional to return if the first is None.
Returns O | O2
The first Optional if Some, otherwise the alternative.
Example
```
const preferred = Optional.some('primary');
const fallback = Optional.some('secondary');
const noneValue = Optional.none as Optional<string>;

assert.deepStrictEqual(Optional.orElse(preferred, fallback), preferred);
assert.deepStrictEqual(Optional.orElse(noneValue, fallback), fallback);

const orElseFallback = Optional.orElse(Optional.some('default'));

assert.deepStrictEqual(orElseFallback(Optional.none), Optional.some('default'));
assert.deepStrictEqual(
  orElseFallback(Optional.some('value')),
  Optional.some('value'),
);
```
- Defined in src/functional/optional.mts:366
orElse<S, S2>(
alternative: Optional<S2>,
): (
optional: Optional<S>,
) => Readonly<{}> | Readonly<{ value: S2 }> | Readonly<{ value: S }>
Returns the Optional if it is Some, otherwise returns the alternative.

Provides a way to chain Optional operations with fallback values. This is particularly useful for implementing default behavior or cascading lookups. Supports both direct usage and curried form for functional composition.
Type Parameters
- S
- S2
Parameters
- alternative: Optional<S2>
  The alternative Optional to return if the first is None.
Returns (
optional: Optional<S>,
) => Readonly<{}> | Readonly<{ value: S2 }> | Readonly<{ value: S }>
The first Optional if Some, otherwise the alternative.
Example
```
const preferred = Optional.some('primary');
const fallback = Optional.some('secondary');
const noneValue = Optional.none as Optional<string>;

assert.deepStrictEqual(Optional.orElse(preferred, fallback), preferred);
assert.deepStrictEqual(Optional.orElse(noneValue, fallback), fallback);

const orElseFallback = Optional.orElse(Optional.some('default'));

assert.deepStrictEqual(orElseFallback(Optional.none), Optional.some('default'));
assert.deepStrictEqual(
  orElseFallback(Optional.some('value')),
  Optional.some('value'),
);
```
- Defined in src/functional/optional.mts:372

Function orElse

Type Parameters

Parameters

Returns O | O2

Example

Type Parameters

Parameters

Returns ( optional: Optional<S>,) => Readonly<{}> | Readonly<{ value: S2 }> | Readonly<{ value: S }>

Example

Settings

Returns (
optional: Optional<S>,
) => Readonly<{}> | Readonly<{ value: S2 }> | Readonly<{ value: S }>