App Hotkeys Guide

@hotkey and HotkeyController register a hotkey while its component is mounted. A cheat sheet built from live registrations therefore misses hotkeys on routes that have not rendered yet, and a settings screen has nowhere to change them. App hotkeys solve both: you declare every hotkey in one place, publish them with provideAppHotkeys, and attach callbacks where the work happens. Users can then customize any of them, and your app decides how to save their choices.

A declaration holds a hotkey's id, default hotkey, metadata, and options. It never holds a callback; @hotkey and HotkeyController still attach the callbacks.

Declare app hotkeys#

Use defineAppHotkeys in a module that contains only declarations. Keep it free of components and handlers, because it loads with your app shell:

// app-hotkeys.ts
import { defineAppHotkeys } from '@tanstack/lit-hotkeys'

export const appHotkeys = defineAppHotkeys({
  'doc.save': { hotkey: 'Mod+S', meta: { name: 'Save', group: 'Document' } },
  'doc.find': {
    hotkey: 'Mod+F',
    meta: { name: 'Find', group: 'Document' },
    context: 'editor',
  },
  'nav.home': {
    hotkey: ['G', 'H'],
    meta: { name: 'Go home', group: 'Navigation' },
    options: { timeout: 800 },
  },
  'palette.open': { hotkey: null, meta: { name: 'Command palette' } },
})

declare module '@tanstack/lit-hotkeys' {
  interface Register {
    appHotkeys: typeof appHotkeys
  }
}

• The object key is the app hotkey's id. Treat ids as a stable contract, because saved custom hotkeys use them as keys.
• hotkey is the default: a chord, a sequence, or null for an action without a default. An unbound app hotkey registers nothing until the user assigns one.
• options describe the hotkey itself: conflictBehavior, eventType, ignoreInputs, preventDefault, stopPropagation, plus requireReset for a chord default or timeout for a sequence default. Options that don't match the default's kind are type errors. Pass target and enabled where you register the hotkey.
• context labels where a hotkey applies, such as 'editor'. App hotkeys with different contexts may share a hotkey. It is used only for conflict checks and does not affect matching.

The Register augmentation types the app hotkeys you read back, the ids accepted when changing custom hotkeys, and the CustomHotkeys type.

Provide app hotkeys#

// main.ts, before your elements render
import { provideAppHotkeys } from '@tanstack/lit-hotkeys'
import { appHotkeys } from './app-hotkeys'

provideAppHotkeys(appHotkeys)

Lit has no provider component. provideAppHotkeys creates the shared AppHotkeysStore and publishes it for controllers, decorators, and devtools. Call it once at startup; it returns { store, dispose }.

Register app hotkeys#

Pass an app hotkey wherever you pass a hotkey:

import { LitElement } from 'lit'
import { property } from 'lit/decorators.js'
import { HotkeyController, hotkey } from '@tanstack/lit-hotkeys'
import { appHotkeys } from './app-hotkeys'

class Editor extends LitElement {
  @property({ type: Boolean }) dirty = false

  @hotkey(appHotkeys['nav.home'])
  goHome() {}

  constructor() {
    super()
    this.addController(
      new HotkeyController(this, appHotkeys['doc.save'], () => this.save(), () => ({
        enabled: this.dirty,
      })),
    )
  }
}

Controllers and decorators look up the published store, so the registration follows the user's custom hotkey even though you import the declaration directly. Without provided app hotkeys, the declared default is used.

The registration takes meta and options from the declaration. Options merge in this order: default options, then declared options, then call-site options. meta comes only from the declaration, so the cheat sheet and the registration cannot disagree. Call-site options are typed by the declared default's kind, so timeout is accepted for nav.home but not for doc.save.

When the user changes a hotkey, registered app hotkeys move to the new hotkey immediately, even if it changes from a chord to a sequence.

Build a cheat sheet#

AppHotkeysController.list returns every app hotkey in declaration order, with its live status:

import { AppHotkeysController, formatForDisplay } from '@tanstack/lit-hotkeys'

class CheatSheet extends LitElement {
  private app = new AppHotkeysController(this)

  render() {
    return html`<ul>
      ${this.app.list.map(
        ({ appHotkey, status, isCustom }) => html`
          <li data-status=${status}>
            ${appHotkey.meta?.name}:
            ${appHotkey.hotkey ? formatForDisplay(appHotkey.hotkey) : 'Unassigned'}
            ${isCustom ? '(custom)' : ''}
          </li>
        `,
      )}
    </ul>`
  }
}

AppHotkeysController also exposes the effective appHotkeys and the custom hotkey actions below, and requests an update whenever any of them change.

An app hotkey registered by many components, such as one per list row, appears once. Its registrations array holds each live registration. Devtools also list declared app hotkeys that are not registered.

Customize and persist hotkeys#

TanStack Hotkeys does not store anything. Pass the user's saved custom hotkeys in and save them when they change:

import { provideAppHotkeys } from '@tanstack/lit-hotkeys'

provideAppHotkeys(appHotkeys, {
  customHotkeys: JSON.parse(localStorage.getItem('hotkeys') ?? '{}'),
  onCustomHotkeysChange: (custom) =>
    localStorage.setItem('hotkeys', JSON.stringify(custom)),
})

• customHotkeys holds only the hotkeys that differ from the declared defaults, keyed by id. null means the user unbound that hotkey. Saving differences means users who never changed a hotkey get new defaults when you change them.
• customHotkeys is read once; afterwards the shared store owns the state. Saved data can outlive the code that wrote it, so unknown ids and invalid hotkeys are ignored with a warning.
• onCustomHotkeysChange receives the complete custom hotkeys after every change, ready to save. Storage can be anything: local storage, a server, or a user profile.

Recorded hotkeys use Mod rather than platform-specific modifiers, so a hotkey saved on one platform works on others.

Change hotkeys#

AppHotkeysController reads and changes the user's custom hotkeys:

import {
  AppHotkeysController,
  HotkeyRecorderController,
  formatForDisplay,
} from '@tanstack/lit-hotkeys'
import type { AppHotkeyId } from '@tanstack/lit-hotkeys'

class ShortcutRow extends LitElement {
  @property() hotkeyId!: AppHotkeyId
  private app = new AppHotkeysController(this)

  private recorder = new HotkeyRecorderController(this, () => ({
    maxSteps: 3,
    validate: (hotkey) => {
      const conflicts = this.app.findConflicts(this.hotkeyId, hotkey)
      return conflicts.length === 0 || `Used by ${conflicts[0]?.meta?.name}`
    },
    onRecord: (hotkey) => this.app.setCustomHotkey(this.hotkeyId, hotkey),
    onClear: () => this.app.setCustomHotkey(this.hotkeyId, null),
  }))

  render() {
    const appHotkey = this.app.appHotkeys[this.hotkeyId]
    return html`
      ${appHotkey.meta?.name}:
      ${appHotkey.hotkey ? formatForDisplay(appHotkey.hotkey) : 'Unassigned'}
      <button @click=${() => this.recorder.startRecording()}>Change</button>
      <button @click=${() => this.app.resetCustomHotkey(this.hotkeyId)}>Reset</button>
    `
  }
}

Two app hotkeys conflict when their contexts match or either has no context, and their hotkeys collide: equal chords, or one sequence starts with the other, including a sequence whose first step equals a chord. Conflicts are checked across every declaration, whether or not it is registered.

Each app hotkey's defaultHotkey holds its declared default, and each cheat sheet item's isCustom reports whether the effective hotkey differs from it.