key-event-to-string

JavaScript keyboard events to strings

This library helps converting the event object of a JavaScript keydown event into a humanly readable format. The idea is to use this for UI components that let the user choose keyboard shortcuts.

In other words: This library provides the inverse functionality to common keyboard shortcut binding libraries like keymaster or Mousetrap.

Installation

$ npm install --save key-event-to-string

Usage

var event2string = require('key-event-to-string')(options)

document.body.onkeydown = (e) => {
	var keys = event2string(e)
	console.log(keys) // e.g. "Ctrl + A"
}

Options

options is optional and can be an object with the following properties:

key	value	default value
cmd	What string to display for the Cmd/Meta modifier	"Cmd"
ctrl	What string to display for the Ctrl modifier	"Ctrl"
alt	What string to display for the Alt/Option modifier	"Alt"
shift	What string to display for the Shift modifier	"Shift"
joinWith	The string that's displayed between all keys	" + "

For example this could be used to get the Mac style keyboard shortcut strings:

{
	cmd: "⌘",
	ctrl: "⌃",
	alt: "⌥",
	shift: "⇧",
	joinWith: ""
}

The default settings are compatible with the format that common keyboard shortcut libraries, like keymaster or Mousetrap, accept.

Detailed information

require('key-event-to-string').details(e) can be used to get more details. This can be useful for validating keyboard shortcuts, e.g. for requiring a modifier and a normal key. It returns an object with this information:

• hasModifier: True iff atleast one of cmd, ctrl, alt or shift was pressed
• hasKey: True iff a key other than a modifier is pressed
• map: An object containing information which modifier is active and what other key is pressed

Disclaimer

• This library is meant to parse only keydown events. keypress / keyup events have small differences, e..g. keydown is needed to capture Command on a Mac. So keydown is advisible for this anyways.
• I wrote this library for an Electron side project, so I only needed it to run in the Chrome runtime. It probably won't work well in old browsers
• JavaScript keyCodes don't work well with special international characters. E.g. the German umlaut ö has the same keyCode as ;, on a German keyboard. This library doesn't try to fix that and I don't think there's a good fix for all those special cases. Other keyboard shortcut libraries (Mousetrap/keymaster e.g.) have the same problem, so it shouldn't be a big problem since this library is meant to be used as a helper for those libraries