operateclass/index.js

you can add className or remove className at dom

'use strict';

export function addClass(el, className) {
  if (hasClass(el, className)) {
    return ''
  } else {
    // 没有该class则在该元素上新添加class名
    let newClass = el.className.split(' ')
    newClass.push(className)
    el.className = newClass.join(' ')
  }
}
/**
 * 验证是否有该class名
 * @param {*} el dom元素
 * @param {*} className class名
 */
export function hasClass(el, className) {
  let reg = new RegExp('(^|\\s)' + className + '($|\\s)')
  return reg.test(el.className)
}

export function removeClass(el, className) {
  if (hasClass(el, className)) {
    el.className = el.className.replace(new RegExp('(\\s|^)' + className + '(\\s|$)'), ' ')
  } else {
    return ''
  }
}