jsLittle源码封装对象合并

JSLi.extend = JSLi.fn.extend = function () {
    var options, name, src, copy,
    target = arguments[0],i = 1,
    length = arguments.length,
    deep = false;
    //处理深拷贝的情况
    if (typeof (target) === "boolean")
        deep = target,target = arguments[1] || {},i = 2;
    //处理时，目标是一个字符串或（深拷贝可能的情况下）的东西
    if (typeof (target) !== "object" && !toString.call(target) == '[object Function]')
        target = {};
    //扩展JSLite的本身，如果只有一个参数传递
    if (length === i) target = this,--i;
    for (; i < length; i++) {
        if ((options = arguments[i]) != null) {
            for (name in options) {
                src = target[name],copy = options[name];
                if (target === copy) continue;
                if (copy !== undefined) target[name] = copy;
            }
        }
    }
    return target;
};