lib/Ext/util/Collection.js
function(fn, scope) {
        var keys = this.keys,
            items = this.items,
            ln = keys.length, i;

        for (i = 0; i < ln; i++) {
            fn.call(scope || window, keys[i], items[i], i, ln);
        }
    }
function(fn, scope) {
        var keys = this.keys,
            items = this.items,
            ln = keys.length, i;

        for (i = 0; i < ln; i++) {
            fn.call(scope || window, keys[i], items[i], i, ln);
        }
    }
Executes the specified function once for every key in the collection, passing each key, and its associated item
as the first two parameters.
@param {Function} fn The function to execute for each item.
@param {Object} scope The scope (`this` reference) in which the function is executed. Defaults to the browser
window.