> 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/map.md).

# map

> A mutable key-value map type

Use `map` when you need a mutable key-value map object with explicit methods for reading keys and values.

```javascript
import "std:map"
```

## Example

```javascript
import "std:map"

map users = map()
users.set("ada", 36)
log users.get("ada")
```

## API reference

### `Map` values

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

| Method                      | Returns  | Description                                           |
| --------------------------- | -------- | ----------------------------------------------------- |
| `value.set(k: any, v: any)` | `*Map`   | Sets a value after shared comparable-key validation.  |
| `value.get(k: any)`         | `any`    | Reads through the same comparable-key guard.          |
| `value.delete(k: any)`      | `void`   | Deletes through the same comparable-key guard.        |
| `value.size()`              | `number` | Returns the number of stored values.                  |
| `value.clear()`             | `void`   | Clears all stored values.                             |
| `value.getKeys()`           | `K[]`    | Returns keys while preserving the map's key type.     |
| `value.getValues()`         | `V[]`    | Returns values while preserving the map's value type. |

## Notes

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

Maps and sets use one runtime comparable-value guard for composite and cyclic keys, and shared maps synchronize concurrent reads and writes.