key-commander

A centralised keyboard listener for parts of an application to subscribe to.

Runs a single event listener for keyup, keydown, and keypress that can be subscribed to, and the functions you pass in will not be called unless all defined option criterias are satisfied.

You can find a list of accepted special characters here eg: ArrowUp

Install

Using npm

npm i key-commander

Using yarn

yarn add key-commander

API

const kc = {
  subscribe: (key: string, func, options) => subId: string,
  unsub: (subId: string) => void,
  getList: () => Array<{
    id: string,
    key: string,
    func,
    options,
  }>
}

// ---

func: (
  event: KeyboardEvent,
  {
    // Use this to determine if the currently focused element
    // when then event occurs has a tab index such as an input
    // where you may not want to trigger your function
    onTabElement: boolean,
  }
) => void
options: {
  /**
   * At what stage of the user input you would like the function called
   *
   * default: keydown
   */
  event: 'keyup' | 'keydown' | 'keypress'
  /**
   * If you want the function called only when one or more modifiers are active
   * You may experience issues with alt/meta modifiers depending on browsers as
   * they may be attached to other browser functionality.
   *
   * Can also pass `'none'` if you want to specifically trigger only if no modifiers are pressed
   *
   * default: void
   */
  modifier: void | 'alt' | 'ctrl' | 'meta' | 'shift' | Array<'alt' | 'ctrl' | 'meta' | 'shift'>
  /**
   * If you want the function called multiple times if the user holds down a particular key
   *
   * default: false
   */
  onRepeat: boolean
}

Usage

import KeyCommander from 'key-commander';

const kc = new KeyCommander();

const subId = kc.subscribe('escape', () => {});

kc.unsub(subId);

With React:

import React from 'react';
import KeyCommander from 'key-commander';

const kc = new KeyCommander();

const Comp = () => {
  useEffect(() => {
    const id = kc.subscribe('b', (event, { onTabElement }) => {
      if (!onTabElement) {
        // close menu
      }
    }, { onRepeat: true });

    return () => {
      kc.ubsub(id);
    };
  });

  return <div />;
}

Single Instance

Alternatively, if you don't want to manage your own instance you can have key-commander run its own that's stored in an abstracted window object. Otherwise you can manage the instance yourself, by passing the functionality through react context for example.

import kc from 'key-commander/instanced';

You can also simplify this with module resolution with webpack module alias so you only need to type import kc from 'key-commander' when importing.

const webpackConfig = {
  // other options ...
  resolve: {
    alias: {
      'key-commander': 'key-commander/instanced',
    },
    // other resolvers ...
  },
  // other options ...
};

If resolving imports and using flow you may find you're not getting proper typings anymore. To fix this you can update your .flowconfig with module.name_mapper.

[options]
module.name_mapper='^key-commander$' -> 'key-commander/instanced'
# other options ...