JSON 合并

// 模仿 Object.assign()
function JSON_merge() {
    var json = {},
        args = arguments,
        copy = function(f, s) {
            if (!Object.keys(s).length || f === null) return;
            for (var i in s) {
                if (typeof s[i] === 'object' && !!s[i]) {
                    f[i] = s[i].constructor === Array ? [] : {};
                    copy(f[i], s[i]);
                }
                else {
                    f[i] = s[i];
                }
            }
            return f;
        };

    for (var i in args) {
        if (!args[i] || args[i].constructor !== Object) throw new Error('arguments has issue!');
        copy(json, args[i]);
    }
    return json;
}