<property>Changed arguments for arrays differ based on type of change

[alltom]

http://jsbin.com/ronarodiyu/1/edit

Polymer('tag-name', {
  created: function() {
    this.array = [];

    setTimeout(function () {
      console.log('push');
      this.array.push('asdf');
    }.bind(this), 1000);

    setTimeout(function () {
      console.log('replace');
      this.array = [];
    }.bind(this), 2000)
  },
  arrayChanged: function () {
    console.log(arguments);
  },
});

When a value is pushed, arrayChanged is called with the splice. When the array's value is replaced, arrayChanged is called with the old value, the new value, and some other object.

Is this a bug? If I want to use the arguments, how should I tell which way the function was called? arguments.length?

[tjsavage]

Closing this issue due to age and the release of version 1 of Polymer - please feel free to re-open if this is incorrect.