imclab / kb-controls

present a polling interface for keyboard state given a binding object

kb-controls

expose a polling object for (game) keybindings using vkey definitions.

var kb = require('./index')
  , raf = require('raf')

var ctl = kb({
  '<left>': 'strafe_left'
, '<right>': 'strafe_right'
, '<up>': 'forward'
, '<down>': 'backward'
, 'W': 'forward'
, 'A': 'strafe_left'
, 'S': 'backward'
, 'D': 'strafe_right'
, '<mouse 1>': 'fire'
})

raf(document.body).on('data', function(dt) {
  console.log(!!ctl.forward)
})

Why not events?

Events are great! I love them. But when you're writing game logic, oftentimes you want the frame event to drive the simulation -- and dealing with the keyboard as a separate evented interface can be troublesome in this regard.

API

kb = require('raf')

return the kb function.

ctl = kb([DOMElement,] bindings[, augmentObject])

Add event listeners to DOMElement or document.body if not provided.

Bindings is a map of vkey's to desired property names:

// bindings example
{ 'X': 'do_something'
, '<space>': 'jump'
, '<control>': 'sprint' }

// would yield the following ctl object (sans methods):
{ 'do_something': 0
, 'jump': 0
, 'sprint': 0 }

If augmentObject is passed, these property names will be attached to it instead of a new object.

ctl[yourPropertyName] -> Number

If the number is truthy, that means it's actively being pressed. Otherwise it's not. If it's greater than 1, then two different keys may have been bound to the action and are simultaneously being pressed.

ctl.enable()

Enables the keyup, keydown, mouseup, and mousedown listeners (and makes them preventDefault().)

ctl.enabled() -> boolean

Returns whether or not the ctl is enabled.

ctl.disable()

Disables the DOM listeners (without removing them). Keyboard and mouse events should work as normal while the ctl is disabled.

ctl.destroy()

Removes all DOM event listeners and renders the ctl inert.

License

MIT