JavaScript: Operate on class name of dom elements

css-class-name.js

module.exports = {
  hasClassName: function(element, name) {
    return new RegExp('(?:^|\\s+)' + name + '(?:\\s+|$)').test(element.className);
  },

  addClassName: function(element, name) {
    if (!this.hasClassName(element, name)) {
      element.className = element.className ? [element.className, name].join(' ') : name;
    }
  },

  removeClassName: function(element, name) {
    if (this.hasClassName(element, name)) {
      var c = element.className;
      element.className = c.replace(new RegExp('(?:^|\\s+)' + name + '(?:\\s+|$)', 'g'), '');
    }
  }
};