封装个StringBuffer，用array join的方式拼接字符串

(function(window) {
    var core_ArrPro = Array.prototype;
    var core_slice = core_ArrPro.slice;
    var core_push = core_ArrPro.push;
    var core_unshift = core_ArrPro.unshift;

    function StringBuffer() {
        this.buffer = [];
    }
    StringBuffer.prototype = {
        push: function() {
            core_push.apply(this.buffer, core_slice.call(arguments));
            return this;
        },
        unshift: function() {
            core_unshift.apply(this.buffer, core_slice.call(arguments));
            return this;
        },
        toString: function() {
            return this.buffer.join('');
        }
    };
    return window.StringBuffer = StringBuffer;
})(window);
document.getElementById('result').innerHTML = new StringBuffer().push('asdasd').unshift('654', 123).push(123, 564, 'sdf');

 由于apply效率低于call，而大多push操作只有1个参数，随更新为如下：

(function(window) {
                var core_ArrPro = Array.prototype;
                var core_slice = core_ArrPro.slice;

                function StringBuffer() {
                    this.buffer = [];
                }
                StringBuffer.prototype = {
                    push: function() {
                        if(arguments.length == 1){
                            this.buffer.push(arguments[0])
                        }else if(arguments.length > 1){
                            this.buffer = this.buffer.concat(core_slice.call(arguments));
                        }
                        return this;
                    },
                    unshift: function() {
                        if(arguments.length == 1){
                            this.buffer.unshift(arguments[0])
                        }else if(arguments.length > 1){
                            this.buffer = core_slice.call(arguments).concat(this.buffer)
                        }
                        return this;
                    },
                    toString: function() {
                        return this.buffer.join('');
                    }
                };
                return window.StringBuffer = StringBuffer;
            })(window);
            document.getElementById('result').innerHTML = new StringBuffer().push('asdasd').unshift('654', 123).push(123, 564, 'sdf');