DOMTokenList Prototype Extensions

gistfile1.js

// Usage: `dom_element.classList.addAll(["foo", "bar"], "baz")` and `dom_element.classList.removeAll("foo", ["bar", "baz"])`
// See http://jsbin.com/obenin for demo
(function() {
  var args;
  var flattenArgs = function(collection) {
    if (typeof collection === "string") {
      args.push(collection);
      return;
    }
    collection = Array.prototype.slice.call(collection);
    collection.forEach(function(arg) {
      if (typeof arg === "string") {
        args.push(arg);
        return;
      }
      if (typeof arg === "object" && arg.slice) {
        flattenArgs(arg);
      }
    });
  };
  
  var changeAll = function(list, method) {
    var t = this;
    args = [];
    flattenArgs(list);
    args.forEach(function(val) {
      t[method](val);
    });
  };
  
  DOMTokenList.prototype.addAll = function() {
    changeAll.call(this, arguments, "add");
  };
  
  DOMTokenList.prototype.removeAll = function() {
    changeAll.call(this, arguments, "remove");
  };
})();