# useHotkeys

Source: https://sdk.pdf.net/docs/v1/reference/useHotkeys



Installs window-level keyboard shortcuts. See [Building a PDF application](https://sdk.pdf.net/docs/v1/guides/building-a-pdf-application) for the hotkeys walkthrough.

```ts
useHotkeys(mapping)
```

* `mapping` is a record of key strings to handlers. Keys are modifier chains ending with the key name, such as `Mod-z`, `Shift-Mod-z`, or `Backspace`; `Mod` means Cmd on macOS and Ctrl elsewhere.
* Each handler is a `HotkeyHandler`: a function with no arguments returning `boolean | void`. A handled shortcut consumes the event; return `false` to report it unhandled, so the browser default is kept and the key reaches whatever else expects it.
* The shortcuts listen on the whole window, including while the user types in an input. Wrap a handler with [createUnfocusedHandler](https://sdk.pdf.net/docs/v1/reference/createUnfocusedHandler) for block shortcuts, such as Backspace deleting the selected blocks, or with [createViewportHandler](https://sdk.pdf.net/docs/v1/reference/createViewportHandler) for text formatting shortcuts, so they don't fire where they don't belong.
* The mapping must be memoized, or the listener re-installs on every render.
* Pass a falsy value instead of a mapping to disable the hotkeys, such as while a modal is open.

## Example [#example]

```tsx
import { useMemo } from 'react'
import {
  createUnfocusedHandler,
  useDeleteSelection,
  useHotkeys,
  useUndoRedo,
} from '@sdk-pdf/react'

function useDocumentHotkeys({ areDisabled }: { areDisabled: boolean }) {
  const { undo, redo } = useUndoRedo()
  const deleteSelection = useDeleteSelection()

  useHotkeys(
    useMemo(
      () =>
        !areDisabled && {
          'Mod-z': undo,
          'Shift-Mod-z': redo,
          Backspace: createUnfocusedHandler(deleteSelection),
        },
      [areDisabled, undo, redo, deleteSelection]
    )
  )
}
```