# useModifierKey

**Kind:** Function

**Source:** [`atloria-monorepo/apps/web/src/hooks/useModifierKey.ts`](https://github.com/sherkety/atloria/blob/main/atloria-monorepo/apps/web/src/hooks/useModifierKey.ts#L19)

The ⌘/Ctrl label for a keyboard hint, decided AFTER mount.

Read during render this is a hydration bug, and a subtle one: the server has no `navigator`
so it renders "Ctrl", a Mac browser renders "⌘", and React throws the whole subtree away and
re-renders it client-side (#418). It never showed up in local development because the dev
server and the browser were the same machine — it only appeared once the server was a Linux
container and the reader was on a Mac, which is to say: in front of customers, on every page
carrying the ⌘K search hint.

So the first client render deliberately agrees with the server ("Ctrl") and the real symbol
arrives on the next tick. The cost is one frame showing the wrong modifier on a Mac; the
alternative was discarding the server-rendered page.

## Signature

```ts
function useModifierKey(): '⌘' | 'Ctrl'
```

**Returns:** `'⌘' | 'Ctrl'`