 
 AtomModifierRegex = /(ctrl|alt|shift|cmd)$/
 WhitespaceRegex = /\s+/
+LowerCaseLetterRegex = /^[a-z]$/
+UpperCaseLetterRegex = /^[A-Z]$/
 
 KeyboardEventModifiers = new Set
 KeyboardEventModifiers.add(modifier) for modifier in ['Control', 'Alt', 'Shift', 'Meta']

      keystroke += '-' if keystroke
      keystroke += 'shift'
    # Only upper case alphabetic characters like 'a'
    key = key.toUpperCase() if /^[a-z]$/.test(key)
  else
    key = key.toLowerCase() if /^[A-Z]$/.test(key)
  if event.metaKey
    keystroke += '-' if keystroke
    keystroke += 'cmd'

      else
        return false

  modifiers.add('shift') if UpperCaseLetterRegex.test(primaryKey)
  if modifiers.has('shift') and LowerCaseLetterRegex.test(primaryKey)
    primaryKey = primaryKey.toUpperCase()

  keystroke = []
  keystroke.push('ctrl') if modifiers.has('ctrl')
