npm package: @reaviz/ctrl-keys
Description: A tiny, super fast, typescript library to handle keybindings efficiently.
Author: Amine Ben hammou
Latest version: 1.0.0

# ctrl-keys

A tiny, super fast, typescript library to handle keybindings efficiently.

[![Bundle size](https://img.shields.io/bundlephobia/minzip/ctrl-keys?style=flat-square)](https://bundlephobia.com/result?p=ctrl-keys)
[![Tests Status](https://img.shields.io/github/actions/workflow/status/webneat/ctrl-keys/tests.yml?branch=main&style=flat-square)](https://github.com/webneat/ctrl-keys/actions?query=workflow:"Tests")
[![Coverage Status](https://img.shields.io/coveralls/github/webNeat/ctrl-keys/master?style=flat-square)](https://coveralls.io/github/webNeat/ctrl-keys?branch=master)
[![Version](https://img.shields.io/npm/v/ctrl-keys?style=flat-square)](https://www.npmjs.com/package/ctrl-keys)
[![MIT](https://img.shields.io/npm/l/ctrl-keys?style=flat-square)](LICENSE)

# Contents
- [Features](#features)
- [Installation](#installation)
- [Simple usage in 3 steps](#simple-usage-in-3-steps)
- [Exploring the `ctrl-keys` API](#exploring-the-ctrl-keys-api)
  - [Defining keybindings](#defining-keybindings)
  - [Adding new keybindings](#adding-new-keybindings)
  - [Removing keybindings](#removing-keybindings)
  - [Disabling and enabling keybindings](#disabling-and-enabling-keybindings)
  - [Handling keyboard events](#handling-keyboard-events)
- [Comparaison with other keybindings libraries](#comparaison-with-other-keybindings-libraries)
- [Changelog](#changelog)

# Features
- Zero code dependencies (Uses [`just-types`](https://github.com/webNeat/just-types) for types).
- Small bundle size **< 2kb**.
- Super fast performance ([see benchmark](#performance-comparaison)).
- Fully typed, offers autocomplete for keybindings.
- Handles multi-keys sequences like `ctrl+k ctrl+b` (Inspired by [vscode keybindings](https://code.visualstudio.com/docs/getstarted/keybindings#_keyboard-rules)).
- Does not add global listeners to the `window`, instead it lets you create multiple handlers and bind them to any DOM elements.
- Dynamically add, remove, enable, and disable keybindings.

# Installation

You can install it using `npm` or `yarn`
```bash
npm i ctrl-keys
// or
yarn add ctrl-keys
```
Or use it directly on modern browsers
```html
<script type="module">
  import keys from 'https://unpkg.com/ctrl-keys/dist/index.mjs'
  // ...
</script>
```

_if you need to use this library on an old browser that doesn't support es modules, please open an issue and I will add a CDN that works for you_

# Simple usage in 3 steps

```ts
import keys from 'ctrl-keys'

// 1. Create a keybindings handler
const handler = keys()

// 2. Add keybindings
handler
  .add('ctrl+up', () => {
    // do something
  })
  .add('ctrl+shift+space', 'ctrl+shift+c', () => {
    // do something else ...
  })

// 3. Handle events
window.addEventListener('keydown', handler.handle)
```

That's it. Now:
- Whenever the `ctrl` and `up` keys are pressed at the same time; the first function will be called.
- Whenever `ctrl`, `shift` and `space` keys are pressed then right after `ctrl`, `shift` and `c` are pressed; the second function will be called.

Let's explore what `ctrl-keys` has to offer in more details in the next section.

# Exploring the `ctrl-keys` API

The default export of `ctrl-keys` is a function that takes no argument and returns a new keybindings handler:

```ts
function keys(): Handler
```

The handler has the following interface

```ts
interface HandlerInterface {
  add(...keys: Keys, fn: Callback): this
  remove(...keys: Keys, fn: Callback): this
  enable(...keys: Keys): this
  disable(...keys: Keys): this
  handle(event: KeyboardEvent): boolean
}
```

- `add` method binds some `keys` to a function `fn` so that whenever the keys are pressed on the keyboard, that function is called.
- `remove` removes the binding of `keys` to the function `fn`.
- `disable` can be used to temporary disable some keys (not trigger the functions associated to them) and `enable` is used to enable them again.
- `handle` handles a `KeyboardEvent` (the event emitted by `keydown` for example).

We will take a deeper look to each one of these methods bellow. But first, let's see what values can we give as `keys`.

## Defining keybindings

The methods `add`, `remove`, `enable` and `disable` can take **from 1 to 4** `keys`.

A key is represented by a string in the following format `{modifiers}+{character}` where:
- `modifiers` is any combination of the modifiers `ctrl`, `alt`, `shift` and `meta` separated by `+`.
  - Examples: `ctrl+alt`, `shift`, `alt+meta`, `ctrl+alt+meta`.
- And `character` is one of:
  - `a`, `b`, ..., `z`
  - `0`, `1`, ..., `9`
  - `'`, `"`, `~`, `!`, `@`, `#`, `$`, `%`, `^`, `&`, `*`, `(`, `)`, `.`, `-`, `_`, `+`, `=`, `[`, `]`, `{`, `}`, `<`, `>`, `,`, `/`, `?`, `;`, `:`, `\`, `|`
  - `f1`, `f2`, ..., `f23`
  - `space`, `enter`, `tab`, `down`, `left`, `right`, `up`, `end`, `capslock`, `numlock`, `home`, `pagedown`, `pageup`, `backspace`, `delete`, `insert`, `escape`

if you are using Typescript, it will offer autocomplete and help you detect typos when writing keys.

![Typescript Autocomplete](https://raw.githubusercontent.com/webNeat/ctrl-keys/main/screenshots/keys-autocomplete.gif)

## Adding new keybindings

The `add` method lets you add new keybindings to the handler, you do that by specifying the keys that will be pressed and the function to call when they are pressed.

```ts
const handler = keys()
  .add('ctrl+up', fn1)  // add single key binding
  .add('ctrl+left', 'ctrl+up', 'ctrl+right', fn2)  // add multi keys binding
  .add('tab', event => {
    // You can access the keyboard event inside the callbacks
  })
```

You can add multiple functions to the same key
```ts
handler.add('ctrl+enter', fn1)
handler.add('ctrl+enter', fn2)
handler.add('ctrl+enter', fn3)
handler.add('ctrl+enter', fn2)
```
All added functions will be called (in the same order by which they were added) when handling keyboard events that match the given keys. Adding the same function to the same keys mutiple times will only add it once (the `fn2` in the example above will only be called once when `ctrl+enter` is pressed).

## Removing keybindings

The `remove` method does the opposite of `add`, it by removing keybindings from the handler.

```ts
const handler = keys()
  .add('ctrl+a', fn1)
  .add('ctrl+b', fn2)
  .add('ctrl+a', fn3)
// 'ctrl+a' calls `fn1` and `fn3`
// 'ctrl+b' calls `fn2`

handler.remove('ctrl+b', fn2) // now 'ctrl+b' does nothing
handler.remove('ctrl+a', fn1) // now 'ctrl+a' only calls `fn3`
handler.remove('ctrl+a', fn1) // does nothing because `fn1` is not bound to 'ctrl+a'
```

## Disabling and enabling keybindings
The `disable` and `enable` methods let you disable/enable keybindings.

```ts
const handler = keys()
  .add('ctrl+a', fn1)
  .add('ctrl+b', fn2)
  .add('ctrl+a', fn3)
// 'ctrl+a' calls `fn1` and `fn3`
// 'ctrl+b' calls `fn2`

handler.disable('ctrl+a') // now 'ctrl+a' does nothing
// ...
handler.enable('ctrl+a') // now 'ctrl+a' calls `fn1` and `fn3`
```

**Example use case**
```ts
const handler = keys()
  .add('ctrl+a', fn1)
  .add('ctrl+a', fn2)
  .add('ctrl+a', fn3)

window.addEventListener('keydown', handler.handle)
```
This code will run `fn1`, `fn2` and `fn3` whenever `ctrl+a` is pressed. So if the user is typing into a textarea and presses `ctrl+a` to select all text the functions will be called which may not be the behavior we want. In that case, we can use `disable` to disable all `ctrl+a` bindings when the user starts focuses an input or textarea, and use `enable` to enable them again when the user removes focus from the input.

## Handling keyboard events
`ctrl-keys` does not add listeners to `window` automatically, instead it lets you decide where and when to handle keyboard events. So after creating a handler and adding keybindings to it, you need to use its `handle` method to actually handle keyboard events

```ts
window.addEventListener('keydown', event => {
  handler.handle(event)
})
```

**Note** `event.key` is used when matching events against keybindings.

# Comparaison with other keybindings libraries

Before creating this library, I looked around for existing libraries and found some good ones, but none of them provided everything I wanted.

## Some features comparaison

|  | ctrl-keys | [tinykeys](https://github.com/jamiebuilds/tinykeys) | [hotkeys](https://github.com/jaywcjlove/hotkeys) | [shortcuts](https://github.com/fabiospampinato/shortcuts) |
| ---                                                  | ---               | ---     | ---    | ---     | 
| Bundle size                                          | 1.23 kB           | 0.72 kB | 2.5 kB | 4.4 kB  |
| Support for multiple keys sequences                  | ✅ (up to 4 keys) | ✅     | ❌    | ✅      |
| Dynamically add/remove keybindings                   | ✅                | ❌     | ✅    | ✅      |
| Gives handler instead of adding listener to `window` | ✅                | ✅     | ❌    | ❌      |
| Typescript autocomplete for keybindings              | ✅                | ❌     | ❌    | ❌      |

## Performance comparaison

<table><tr><th>library</th><th>duration</th><th>memory usage</th></tr><tr><td>ctrl-keys</td><td>55 ms</td><td>4711 kb</td></tr><tr><td>shortcuts</td><td>58 ms</td><td>4963 kb</td></tr><tr><td>tinykeys</td><td>69 ms</td><td>5056 kb</td></tr></table>

The results above are of a benchmark of handling a 3 keys sequence 1000 times. [Click here for details](https://github.com/webNeat/ctrl-keys/tree/main/benchmark)

# Changelog

**1.0.1 (June 30th 2023)**

- Update dev dependencies and benchmark.
- Fix Typescript types.

**1.0.0 (March 17th 2022)**

- First release.