/* istanbul ignore next */
export function hasClass(el, cls) {
  if (!el || !cls) return false
  if (cls.indexOf(' ') !== -1) throw new Error('className should not contain space.')
  if (el.classList) {
    return el.classList.contains(cls)
  } else {
    return (' ' + el.className + ' ').indexOf(' ' + cls + ' ') > -1
  }
};

/* istanbul ignore next */
export function addClass(el, cls) {
  if (!el) return
  var curClass = el.className
  var classes = (cls || '').split(' ')

  for (var i = 0, j = classes.length; i < j; i++) {
    var clsName = classes[i]
    if (!clsName) continue

    if (el.classList) {
      el.classList.add(clsName)
    } else if (!hasClass(el, clsName)) {
      curClass += ' ' + clsName
    }
  }
  if (!el.classList) {
    el.className = curClass
  }
};

/* istanbul ignore next */
export function removeClass(el, cls) {
  if (!el || !cls) return
  var classes = cls.split(' ')
  var curClass = ' ' + el.className + ' '

  for (var i = 0, j = classes.length; i < j; i++) {
    var clsName = classes[i]
    if (!clsName) continue

    if (el.classList) {
      el.classList.remove(clsName)
    } else if (hasClass(el, clsName)) {
      curClass = curClass.replace(' ' + clsName + ' ', ' ')
    }
  }
  if (!el.classList) {
    el.className = curClass.trim()
  }
};
