# types.FormatSubscription

- **Module:** types
- **Package:** libtmux
- **Language:** TypeScript
- **Kind:** interface
- **Source:** https://github.com/libtmux/libtmux-ts/blob/3fe1ca654b81b8cbf4a13b777a001a3298c87a6f/packages/libtmux/src/types.ts#L586
- **Page:** https://libtmux.org/en/ts/latest/reference/types-formatsubscription/

A format tmux expands and reports whenever its value changes.

Reports arrive as {@link TmuxSubscriptionEvent}. tmux evaluates every
subscription at most once per second, so this reports a change rather than
every intermediate value.

## Example

```ts
{ format: "#{pane_current_command}", name: "cmd", scope: "all-panes" }
```

## Members

- `format` (property): A tmux format string. See `FORMATS` in the tmux manual.
- `name` (property): The caller's label, echoed back on every report.
- `scope` (property): What the format is expanded against. Omitted expands once per session.