> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/packages/utilities/option.md).

# option

> Optional values (`some`/`none`)

Use `option` to model a value that may be present (`some`) or absent (`none`) without relying on `null`.

```javascript
import "std:option"
```

## Example

```javascript
import "std:option"

auto value = some(42)
log value.unwrapOr(0)
```

## API reference

### `Option` values

Methods available on `Option` values returned by this package or constructed by the language.

| Method                   | Returns   | Description                                                   |
| ------------------------ | --------- | ------------------------------------------------------------- |
| `value.isSome()`         | `boolean` | Reports whether the option contains a value.                  |
| `value.isNone()`         | `boolean` | Reports whether the option is empty.                          |
| `value.unwrap()`         | `T`       | Returns through the shared checked accessor or fails.         |
| `value.unwrapOr(def: T)` | `T`       | Returns the contained value or a fallback.                    |
| `value.expect(msg: any)` | `T`       | Uses the same checked accessor with a custom failure message. |

## Notes

* Prefer `import "std:option"`; the older `import "osl/option"` spelling remains supported.
* Return values such as `array` and `object` are regular OSL values unless a returned object section says otherwise.

## Edge-case behavior

`some(null)` remains a present option; presence is not inferred from whether the stored value is null.