I've added into examples/grid/infinite-scroll.js
Code:
var grid = Ext.create('Ext.grid.Panel', {
...
        dockedItems: [{
            xtype: "toolbar",
            dock: "top",
            items: [{
                text: "getById()",
                handler: function(btn, e) {
                    var
                        grid = btn.up("grid");

                    grid.getStore().getById(1);
                }
            }]
        }]
...
});
TypeError: this.data.findBy is not a function
http://localhost/JavaScript/ExtJS/Ex...t-all-debug.js
Line 66104