# selection.OneRelation

- **Module:** selection
- **Package:** libtmux
- **Language:** TypeScript
- **Kind:** typealias
- **Source:** https://github.com/libtmux/libtmux-ts/blob/46cccfef2a546de55ce8b308249b8c76339089a0/packages/libtmux/src/selection.ts#L129
- **Page:** https://libtmux.org/en/ts/latest/reference/selection-onerelation/

```ts
type OneRelation<Where> = | { readonly is: Where | null; readonly isNot?: Where | null }
| { readonly is?: Where | null; readonly isNot: Where | null }
```

How criteria apply to a single related object, which may be absent.

[`null`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/null) matches the absence itself — a pane whose window is no longer in the
snapshot — rather than matching anything.

## Type parameters

- `Where`