Defining a class with Ext.define.

View.js

Ext.define('My.ToDo.View', {
	extend: 'Ext.view.View',
	tpl: '<ul><tpl for="."><li class="todo<tpl if="isDone"> todo-done</tpl>">{description:htmlEncode}</li></tpl></ul>',
	renderTo: Ext.getBody(),
	itemSelector: '.todo',
	baseCls: 'todo-list',
	emptyText: 'No items',
	listeners: {
		itemclick: function (view, record) {
			this.markDone(record);
		}
	},
	markDone: function (record) {
		var isDone = record.get('isDone');

		if (isDone === false) {
			record.set('isDone', true);
		}
	}
});