# builder.windowAt

- **Module:** builder
- **Package:** @libtmux/libtmux
- **Language:** TypeScript
- **Kind:** function
- **Source:** https://github.com/libtmux/libtmux-ts/blob/2cb93308200da38a26b59876618116850f110607/packages/workspace/src/builder.ts#L226
- **Page:** https://libtmux.org/reference/ts/builder-windowat/

```
builder.windowAt(session: : Session, index: : number, desired: : WorkspaceWindow, workspace: : Workspace) -> Promise<{ readonly created: boolean; readonly window: Window }>
```

The window that should hold position `index`, created if it is not there yet.

tmux window indexes are not positions — `base-index` shifts them and a killed
window leaves a gap — so position is resolved by ordinal, not by index.