A few helpful polyfills

polyfills.js

// Array Remove - By John Resig (MIT Licensed)
if (!Array.prototype.remove) {
  Array.prototype.remove = function (from, to) {
    var rest = this.slice((to || from) + 1 || this.length);
    this.length = from < 0 ? this.length + from : from;
    return this.push.apply(this, rest);
  };
}

if (!Array.prototype.indexOf) {
  Array.prototype.indexOf = function (elt /*, from*/) {
    var len = this.length;

    var from = Number(arguments[1]) || 0;
    from = (from < 0) ? Math.ceil(from) : Math.floor(from);
    if (from < 0) { from += len; }

    for (; from < len; from++) {
      if (from in this && this[from] === elt) {
        return from;
      }
    }
    return -1;
  };
}

// https://gist.github.com/384583
// object.watch
if (!Object.prototype.watch) {
  Object.defineProperty(Object.prototype, 'watch', {
      enumerable: false,
      configurable: true,
      writable: false,
      value: function (prop, handler) {
      var
        oldval = this[prop],
        newval = oldval,
        getter = function () {
          return newval;
        },
        setter = function (val) {
          oldval = newval;
          newval = handler.call(this, prop, oldval, val);
          return newval;
        };

      if (delete this[prop]) { // can't watch constants
        Object.defineProperty(this, prop, {
            get: getter,
            set: setter,
            enumerable: true,
            configurable: true
        });
      }
    }
  });
}

// object.unwatch
if (!Object.prototype.unwatch) {
  Object.defineProperty(Object.prototype, 'unwatch', {
      enumerable: false,
      configurable: true,
      writable: false,
      value: function (prop) {
        var val = this[prop];
        delete this[prop]; // remove accessors
        this[prop] = val;
      }
  });
}