class-util.js

/* @flow */

/**
 * Add class with compatibility for SVG since classList is not supported on
 * SVG elements in IE
 */
export function addClass(el, cls) {
  /* istanbul ignore if */
  if (!cls || !(cls = cls.trim())) {
    return;
  }

  /* istanbul ignore else */
  if (el.classList) {
    if (cls.indexOf(' ') > -1) {
      cls.split(/\s+/).forEach(function (c) {
        return el.classList.add(c);
      });
    } else {
      el.classList.add(cls);
    }
  } else {
    var cur = ' ' + (el.getAttribute('class') || '') + ' ';
    if (cur.indexOf(' ' + cls + ' ') < 0) {
      el.setAttribute('class', (cur + cls).trim());
    }
  }
}

/**
 * Remove class with compatibility for SVG since classList is not supported on
 * SVG elements in IE
 */
export function removeClass(el, cls) {
  /* istanbul ignore if */
  if (!cls || !(cls = cls.trim())) {
    return;
  }

  /* istanbul ignore else */
  if (el.classList) {
    if (cls.indexOf(' ') > -1) {
      cls.split(/\s+/).forEach(function (c) {
        return el.classList.remove(c);
      });
    } else {
      el.classList.remove(cls);
    }
    if (!el.classList.length) {
      el.removeAttribute('class');
    }
  } else {
    var cur = ' ' + (el.getAttribute('class') || '') + ' ';
    var tar = ' ' + cls + ' ';
    while (cur.indexOf(tar) >= 0) {
      cur = cur.replace(tar, ' ');
    }
    cur = cur.trim();
    if (cur) {
      el.setAttribute('class', cur);
    } else {
      el.removeAttribute('class');
    }
  }
}