Keymash

The fastest, most flexible keyboard binding library for web apps.

import { keymash, ctrl, shift, press } from 'keymash';

const km = keymash();

// Type-safe, autocompletes, catches typos at compile time
km.bind(ctrl + press.s, () => save());
km.bind(ctrl + shift + press.p, () => commandPalette());

// Want Ctrl+K or Ctrl+O to open search? Use |
km.bind(ctrl + (press.k | press.o), () => openSearch());

Install

npm install keymash

Why Keymash?

Other keyboard libraries make you write "$mod+([0-9])" and hope you got their special syntax right. Keymash uses TypeScript operators that autocomplete.

• International Keyboards — AltGr on European layouts, IME for CJK input, dead key compose sequences. Doesn't break the edge cases other libraries ignore.
• Physical Key Codes — WASD game controls that work on AZERTY, QWERTZ, Dvorak. Bind by position, not character.
• Strong Types — TypeScript operators that autocomplete. Typos caught at compile time, not runtime.
• Tiny and Fast — ~2.86 KB gzipped. O(1) chord lookup using bigint bitmasks. Zero dependencies.
• Modal UIs Made Simple — Multiple instances with independent state. Toggle between vim modes, command palettes, focus traps.
• Conflict Detection — Dev mode warns about duplicate bindings and browser shortcuts you shouldn't override.

Modules

Module	Description	Size
keymash	Full library with introspection and dev warnings	~2.86 KB
keymash/react	React hooks for declarative keyboard binding	~3.79 KB

Quick Examples

Basic Binding

import { keymash, ctrl, press } from 'keymash';

const km = keymash({
  bindings: [
    { combo: ctrl + press.s, handler: () => save(), label: 'Save' },
    { combo: ctrl + press.z, handler: () => undo(), label: 'Undo' },
  ]
});

Scoped to an Element

const editor = document.getElementById('editor');
const editorKm = keymash({
  scope: editor,
  bindings: [
    { combo: ctrl + press.b, handler: () => bold() },
  ]
});
// Only active when focus is inside #editor

React Hook

import { useKeymash, ctrl, press } from 'keymash/react';

function Editor() {
  const { isActive, triggered } = useKeymash({
    bindings: [
      { combo: ctrl + press.s, handler: () => save(), label: 'Save' },
    ],
  });

  return <div>Last action: {triggered?.label}</div>;
}

Documentation

Full documentation, interactive demo, and API reference at zetlen.github.io/keymash.

License

MIT