Centralized Rtl handling

As RTL demands are growing, it would be nice for the name of clarity and sanity, to have a helper in one place, used by all js components

A draft of thoughts below:

const CLASSNAME_START = 'start'
const CLASSNAME_END = 'end'
const ORDER_NEXT = 'next'
const ORDER_PREV = 'prev'
const LEFT = 'left'
const RIGHT = 'right'
const UP = 'top'
const DOWN = 'right'

const isDirection = arg => [LEFT, RIGHT, UP, DOWN].includes(arg)

const isXaxisDirection = arg => [LEFT, RIGHT].includes(arg)

const isYaxisDirection = arg => isDirection(arg) && !isXaxisDirection(arg)

const isOrder = arg => [ORDER_NEXT, ORDER_PREV].includes(arg)

const orderToDirection = order => {
  if (!isOrder(order)) {
    return order
  }

  if (isRTL()) {
    return order === ORDER_PREV ? LEFT : RIGHT
  }

  return order === ORDER_PREV ? RIGHT : LEFT
}

const directionToOrder = arg => {
  if (!isDirection(arg) || isYaxisDirection(arg)) {
    return arg
  }

  if (isRTL()) {
    return arg === LEFT ? ORDER_PREV : ORDER_NEXT
  }

  return arg === LEFT ? ORDER_NEXT : ORDER_PREV
}

const sideToClass = (arg, prefix = '') => {
  if (!isDirection(arg)) {
    return arg
  }

  if (isYaxisDirection(arg)) {
    return addPrefix(arg, prefix)
  }

  if (isRTL()) {
    return addPrefix(arg === LEFT ? CLASSNAME_START : CLASSNAME_END, prefix)
  }

  return addPrefix(arg === LEFT ? CLASSNAME_END : CLASSNAME_START, prefix)
}

const addPrefix = (string, prefix) => {
  return typeof prefix === 'string' && prefix !== '' ? `${prefix}-${string}` : string
}

export {
  isDirection,
  directionToOrder,
  orderToDirection,
  sideToClass
}