Get a notification when a user starts and stops typing on the passed-in `el`.

typing.coffee

# Get a notification when a user starts and stops typing on the passed-in `el`.
#
# Based on https://github.com/narfdotpl/jquery-typing

module.exports = (el, {delay, start, stop}) ->
  delay ||= 400

  typing = false
  timeout = null

  startTyping = ->
    unless typing
      typing = true
      start?()

  stopTyping = ->
    if typing
      clearTimeout timeout
      timeout = setTimeout ->
        typing = false
        stop?()
      , delay


  BACKSPACE_KEY = 8
  DELETE_KEY = 46

  el.addEventListener 'keypress', startTyping

  el.addEventListener 'keydown', (e) ->
    startTyping() if e.keyCode is BACKSPACE_KEY || e.keyCode is DELETE_KEY

  el.addEventListener 'keyup', stopTyping