Ext.js分析

enumerables = true,
enumerablesTest = { toString: 1 },
  for (i in enumerablesTest) {
        enumerables = null;
    }

    if (enumerables) {
        enumerables = ['hasOwnProperty', 'valueOf', 'isPrototypeOf', 'propertyIsEnumerable',
                       'toLocaleString', 'toString', 'constructor'];
    }

要理解上面的话，得明白在ie下for i in obj 里，不能迭代toString等方法
Ext.apply = function(object, config, defaults) { 
        if (defaults) {
            Ext.apply(object, defaults);
        }

        if (object && config && typeof config === 'object') {
            var i, j, k;

            for (i in config) {   拷贝配置属性到obj
                object[i] = config[i];
            }

            if (enumerables) {           //如果是ie
                for (j = enumerables.length; j--;) {
                    k = enumerables[j];
                    if (config.hasOwnProperty(k)) {  //拷贝enumerables里的非native
                        object[k] = config[k];
                    }
                }
            }
        }

        return object;
    };

    applyIf: function(object, config) { 拷贝config里object未定义的配置
            var property;

            if (object) {
                for (property in config) {
                    if (object[property] === undefined) {
                        object[property] = config[property];
                    }
                }
            }

            return object;
        },

iterate: function(object, fn, scope) {  可以迭代对象和数组，执行fn方法
            if (Ext.isEmpty(object)) {
                return;
            }

            if (scope === undefined) {
                scope = object;
            }

            if (Ext.isIterable(object)) {
                Ext.Array.each.call(Ext.Array, object, fn, scope);
            }
            else {
                Ext.Object.each.call(Ext.Object, object, fn, scope);
            }
        }