# HotkeyIssueReason

```ts
type HotkeyIssueReason = 
  | "empty"
  | "empty-part"
  | "unknown-modifier"
  | "invalid-physical-key"
  | "modifier-only"
  | "unknown-key";
```

Defined in: [validate.ts:192](https://github.com/TanStack/hotkeys/blob/main/packages/hotkeys/src/validate.ts#L192)

Why a hotkey is invalid or may never fire:

- `'empty'`: the hotkey or sequence is empty.
- `'empty-part'`: a part between `+` signs is empty or whitespace.
- `'unknown-modifier'`: a modifier isn't one the library knows, such as `Ctl`.
- `'invalid-physical-key'`: a bracketed key isn't a `KeyboardEvent.code`.
- `'modifier-only'`: the key is a modifier, such as `Shift` or `[ShiftLeft]`.
- `'unknown-key'` (warning): the key isn't written like a known key name.
  Key names are case-sensitive, so `escape` never matches `Escape`.