xtype instead of alias in class definition

Question

Is there any difference between the two following class definition methods?

Ext.define("Test", {
  extend: "Ext.grid.Panel",
  xtype: "test"
});

Ext.define("Test", {
  extend: "Ext.grid.Panel",
  alias: "widget.test"
});

Answer 1

As Eddy already stated, there is no difference in the result in case of a xtype.

But the alias property can more then a xtype...

The main difference is that alias can be used to define all sort of aliases (widgets, plugins, features, layouts, etc.) while xtype already is a specific shorthand for a alias type, a widget. So if you use xtype you can only define widgets, nothing else. In addition the alias property makes the code a bit more readable and should therefore be the first choice when writing class definitions.

Here are the common aliases of versions 4.2.3

• association
• axis
• data
• direct
• editing
• feature
• formaction
• idgen
• layout
• plugin
• proxy
• reader
• selection
• series
• state
• store
• widget
• writer

Answer 2

It is said that the alias is faster, but I don't think you will notice. I use alias when defining classes and xtype when creating objects, just a personal convention, so I don't get confused.